Renin, antidiuretic hormone and the kidney in water restriction and rehydration.

1. The effect of restricted water intake followed by voluntary rehydration with water or 10 mM-KCl was studied in four conscious sheep with respect to plasma concentrations of renin, antidiuretic hormone (ADH), protein and electrolytes, and urine flow rate, osmolality and osmolal excretion. 2. Water restriction increased the plasma renin concentration and the plasma ADH concentration. 3. Rehydration with water caused a further rise in plasma renin, but plasma ADH returned to basal levels in less than 2 hr. 4. Rehydration with 10 mM-KCl in order to stabilize plasma K concentration greatly attenuated the post-drinking rise in plasma renin concentration, while plasma ADH levels fell as before. 5. Urine flow rates after rehydration with water and 10 mM-KCl remained low for at least 6 hr in most experiments despite low plasma ADH levels. The effect on urine osmolality ranged from no change to a large drop. 6. The post-drinking antidiuresis was associated with a reduction in solute excretion rate. However, free water clearance usually remained negative. 7. These experiments do not support the existence of a direct nexus between plasma ADH levels and plasma renin concentration.


Studies on amino acid inhibition of monosaccharide exit from anuran small intestinal epithelium.

1. The effect of the addition of amino acids to the intestinal lumen upon the movement of the monosaccharide alpha-methyl-D-glucopyranoside (alpha MG) from the preloaded epithelium into the blood and into the lumen of the vascularly perfused frog small intestine has been studied. 2. The neutral hydrophobic amino acids tryptophan, leucine, phenylalanine, tyrosine, isoleucine, valine, norleucine and cycloleucine all rapidly inhibit the exit of alpha MG out of the epithelium into the vascular bed. They stimulate backflux of the sugar from the epithelium into the lumen to a very much smaller extent. 3. L-Leucine is a more effective inhibitor of alpha MG exit into the blood than is D-leucine. Near-maximal inhibition of alpha MG exit is seen with 10 mM-L-leucine in the intestinal lumen. 4. The addition of leucine (10 mM) to the lumen of the intestine preloaded with alpha MG approximately halves the rate constant for alpha MG washout into the blood from 12.6 +/- 1.7 (4) x 10(-3) to 5.5 +/- 1.4 (4) x 10(-3) min-1, without appreciably altering the pool of monosaccharide in the tissue. The inhibitory effect of L-leucine upon alpha MG exit into the blood is not abolished by the presence of phlorizin (5 x 10(-5) M) in the intestinal lumen. 5. The complex pattern of inhibition of alpha MG transfer from the lumen to the blood observed upon the addition of L-leucine to the lumen is consistent with the finding that the amino acid inhibits the exit of the monosaccharide out of the epithelium into the blood in addition to any inhibitory effect upon sugar entry across the brush border. 6. It is suggested that alpha MG may be a substrate for a proposed transport system for neutral hydrophobic amino acids which, it is suggested, is present in the basolateral membrane of the epithelial cell.


The mechanism of coupled transport of sodium and chloride in isolated urinary bladder of the trout.

1. Transepithelial fluxes of Na and Cl were measured in dissected trout bladders mounted in Ussing chambers. The mucosa-to-serosa fluxes appeared to comprise a linear and a saturating (Km = 8 mM) component as a function of the luminal concentration of the ion. The over-all permeability for Cl was higher than for Na. Removal of either ion from the mucosal side induced the disappearance of the net flux of the co-ion even when the substituting ions were not impermeant. This indicated a complete and specific mutual dependence between the Na and Cl transports. A large part (30-50%) of Cl exchanges was ascribed to an exchange-diffusion process. 2. In order to localize the site of ion copuling, the apical uptakes of Na and Cl were measured by short-term exposure (2 min) to radioisotopes. The apical fluxes were similar to the transepithelial fluxes and therefore appeared to be the limiting factor for ion transfer. Ionic replacements on the mucosal side showed that the coupling between Na and Cl and Cl/Cl exchange occurs at this step.


Intracellular recording from neurones of the rat subfornical organ in vitro.

1. Intracellular recordings from neurones in the subfornical organ in vitro showed that there were two classes of neurones. One class lay within 55 micron of the ventricular surface and was synaptically excited but not inhibited by stimulation of the body or columns of the fornix. These neurones could not be excited antidromically. The other class lay more deeply and was antidromically and synaptically excited and inhibited by stimulation of the body and columns of the fornix. 2. The neurones of the subfornical organ appeared to have the characteristics of neurosecretory neurones. Their action potentials were prolonged and their antidromic spike was easily broken down into components by repetitive stimulation. 3. The organization of the subfornical organ inferred from extracellular recording was confirmed by the results of intracellular recording.


Effect of intraventricular injection of transmitter substances and temperature on autonomic functions of conscious sheep.

1. Changes in cardiovascular and renal functions following injection of noradrenaline, 5-hydroxytryptamine and carbachol into one lateral cerebral ventricle were investigated in conscious sheep at ambient air temperatures of 0 and 40 degrees C. The dose rates used were known to produce predictable changes in thermoregulation in sheep. 2. The changes in body temperature, respiratory frequency and shivering caused by the intracerebroventricular (I.C.V.) injections of noradrenaline, 5-hydroxytryptamine and carbachol were as reported previously. 3. The cardiovascular and renal responses of the sheep at both high and low ambient temperatures were consistent for each transmitter indicating that these activities had no major dependence on the type of thermoregulatory response. 4. I.C.V. injection of noradrenaline increased heart rate and decreased pulse pressure but caused no change in mean arterial blood pressure (B.P.). Urine flow rate, sodium clearance, potassium clearance and osmolal clearance were decreased whereas solute-free water reabsorption was unaltered. 5. I.C.V. injection of 5-hydroxytryptamine caused no significant alterations in either cardiovascular or renal function. 6. I.C.V. injection of carbachol increased systolic and diastolic B.P., heart rate and haematocrit. Sodium, potassium and osmolal clearances were increased after administration of carbachol. 7. The changes in renal function after noradrenaline and carbachol injection could be explained by the concurrent changes in cardiovascular function.


Inotropic and arrhythmogenic effects of potassium-depleted solutions on mammalian cardiac muscle.

1. We have investigated the electrical and mechanical effects of reducing the bathing K concentration, K0, over the range from 4-0 mM in guinea-pig papillary muscle and in sheep Purkinje fibres. 2. In papillary muscle, reducing K0 to zero produces a negative shift in the resting potential and an initial increase in action potential duration. An increase of twitch tension ensues, followed by a reduction in actin potential duration and, eventually, an increase in tonic tension. This increase in tonic tension is often accompanied by a decrease of twitch tension. Finally, transient depolarizations and after contractions are produced. 3. In voltage clamped Purkinje fibres, K0 reduction decreases the slope conductance at the more negative potentials and reduces the pace-maker current, iK2. Twitch tension increases rapidly and voltage dependent tonic tension develops. After even very short exposures to very low K0 (1 mM and below), an oscillatory transient inward current and accompanying aftercontraction can be seen. The oscillatory transient inward current and aftercontraction are similar to those described for cardiotonic steroid intoxication by Kass, Lederer, Tsien & Weingart (1978). 4. Prolonged exposure to 0 K0 leads to the development of a slow current 'creep'. This current is activated by depolarization and has a reversal potential of -6.7 +/- 3.5 mV. The development of this creep current is accompanied by an increasing 'creep' in tonic tension with the same time course. On repolarization both the current creep and creep in tension recover with time courses still similar to each other. 5. Fluctuations appear in both the tension and current records during exposure to low K0. The tension and current fluctuations have similar principal frequencies (about 1 Hz). 6. Ca0 removal, substituting Ba0 for Ca0 or adding Mn0 (2 mM) can each remove the transient inward current, aftercontraction, fluctuations of current and tension, and creep current as well as the increase of twitch and tonic tension. 7. Replacing Ca0 by Sr0 leads to an increased inotropic effect of low K0 with altered kinetics and appears to abolish the transient inward current, aftercontraction and fluctuations of current and tension. 8. It is concluded that Ca1 plays a central role in the inotropic and arrhythmogenic effects of low K0. Possible mechanisms of Ca1 control are discussed in light of the results that have been presented.


The role of the sodium pump in the effects of potassium-depleted solutions on mammalian cardiac muscle.

1. Mammalian Purkinje fibres and ventricular muscle are significantly affected by exposure to low K solutions (Eisner & Lederer, 1979). Such exposure produces two classes of effects. ;Early' effects, developing over tens of seconds include (in ventricular muscle) a more negative resting potential and a lengthening of the action potential. In Purkinje fibres the principal ;early' effect is a decrease in slope conductance. ;Late' effects develop over minutes. In ventricular muscle such effects include a shortening of the action potential, an increase in twitch and tonic tension, and the development of transient depolarizations and aftercontractions. The late effects in Purkinje fibres are the increase in twitch tension and voltage dependent tonic tension, the development of transient depolarizations and the underlying oscillatory transient inward currents, the appearance of aftercontractions accompanying the transient depolarizations or transient inward currents, and the development of a slow ;creep' in both current and tension.2. The rate of development of early effects is consistent with the time taken to change the bathing K concentration, K(o). However the time course of onset of the late effects (including the positive inotropy) is too slow to be explained by the time taken to change K(o).3. The late effects of reducing K(o) from 4 to 0 mM can be prevented by including appropriate concentrations of the activator cations of the Na pump (Tl, Rb, Cs, NH(4) or Li) in the 0 K(o) bathing solution. Similarly the late effects of 0 K(o), once established, can be reversed by adding these cations to the 0 K(o) superfusing solution.4. The order of potency of these cations to remove the effects of 0 K(o) was found to be: Tl > K approximately Rb > NH(4) approximately Cs > Li. This is similar to the order of efficacy shown to activate the external K site of the Na pump in nerve and other tissue (Rang & Ritchie, 1968).5. Strophanthidin (10(-5)M) produces qualitatively similar electrical and mechanical effects as those seen in 0 K(o). However, the effects of strophanthidin are not reversed by the activator cations. Furthermore, in the presence of strophanthidin (10(-5)M), these cations do not reverse the effects of 0 K(o).6. In voltage-clamped Purkinje fibres, returning to a solution of 4 mM-K(o) after exposure to 0 K(o) produces a transient increase in outward current. Similarly, during exposure to 0 K(o) the addition of activator cations also produces a transient increase of outward current. The ability of these ions to develop this outward transient current is correlated with their ability to remove the inotropic and arrhythmogenic effects of 0 K(o).7. The transient outward current produced by activator cations in 0 K(o) is blocked by strophanthidin (10(-5)M). We conclude that the outward current transient reflects activation of an electrogenic Na pump. Furthermore, we find that, as in other tissues, the activator cations can substitute for K(o) in activating the Na-K pump.8. The reversal of inotropic and arrhythmogenic effects of 0 K(o) by activator cations indicates that such effects result from Na pump blockade. No additional explanation (e.g. Ca/K exchange) need be invoked.


Effect of thumb anaesthesia on weight perception, muscle activity and the stretch reflex in man.

1. We have confirmed the results of Gandevia & McCloskey (1977) on the effect of thumb anaesthesia on perception of weights lifted by the thumb. Weights lifted by flexion feel heavier and weights lifted by extension feel lighter. 2. The change in size of the long-latency stretch reflex in flexor pollicis longus or extensor pollicis longus after thumb anaesthesia cannot explain the effect on weight perception by removal or augmentation of the background servo assistance to muscular contraction. 3. During smooth thumb flexion, thumb anaesthesia increases e.m.g. activity in flexor pollicis longus and extensor pollicis longus for any given opposing torque. 4. During smooth thumb extension the opposite occurs: e.m.g. activity in both extensor and flexor pollicis longus decreases. 5. Clamping the thumb at the proximal phalanx to limit movement solely to the interphalangeal joint reduces or abolishes the effect of anaesthesia on both weight perception and e.m.g. activity during both flexion or extension tasks. 6. Gandevia & McCloskey's findings on the distorting effects of thumb anaesthesia on weight perception cannot be used to support the hypothesis of an efferent monitoring system of the sense of effort. Our results emphasize the close functional relationship between cutaneous and joint afferent information and motor control.


Ballistic flexion movements of the human thumb.

1. In response to an auditory stimulus normal subjects made ballistic flexion movements of the top joint of the thumb against a lever attached to the spindle of a low-inertia electric motor. 2. Electromyographic (e.m.g.) activity was recorded from pairs of fine wire electrodes inserted into flexor pollicis longus and extensor pollicis longus, respectively the sole flexor and extensor of the joint. 3. Movements of 5 degrees, 10 degrees and 20 degrees were made from initial angles of 10 degrees, 20 degrees and 30 degrees flexion against torques of 0.04, 0.08 and 0.16 Nm. 4. The e.m.g. activity initiating such movements was characterized by a 'triphasic' pattern of sequential bursts of activity in the agonist (flexor pollicis longus), then in the antagonist (extensor pollicis longus), and then in the agonist again. 5. The duration of the first agonist and first antagonist bursts ranged from about 50 to 90 ms and there was no significant change of burst length in the different mechanical conditions. 6. In movements of differing angular distance, the rectified and integrated e.m.g. activity of the first agonist burst could be correlated with the distance moved. The rectified and integrated e.m.g. activity of the first antagonist burst could not be correlated with the distance moved. 7. Responses of the muscles to perturbations either before or during the ballistic movements were studied. Current in the motor could be altered so to extend the thumb ('stretch'), to allow it to accelerate ('release'), or to prevent further movement ('halt'). 8. Suitably timed stretch increased the e.m.g. activity of the first agonist burst while release decreased it. 9. There was a small response of the agonist to stretch or halt timed to act during the interval between the first two agonist bursts; the major response was an augmentation of the second agonist burst. 10. Stretch, timed to act between the first two agonist bursts which released the antagonist, diminished the activity of the first antagonist burst while halt virtually eradicated it in all but one subject. Release, at this time, which stretched the antagonist, increased the activity of the first antagonist burst. 11. It is concluded that the individual components of a ballistic movement are relatively fixed in duration and the amount of e.m.g. activity is altered within this time interval to produce the different forces required for fast movements of different amplitude. 12. Both agonist and antagonist muscles remain under some feed-back control during the entire course of a ballistic movement, but the amount of influence of fedd-back depends on the supraspinal command signal and the changes in the spindle during the course of the movement.


Neural mechanisms of reflex facilitation and inhibition of gastric motility to stimulation of various skin areas in rats.

1. Experiments were performed on chloralose-urethane anaesthetized rats to determine the involvement of extrinsic gastric autonomic nerves in reflex facilitation and inhibition of gastric motility when mechanical nociceptive stimulation was delivered to either hind paw or abdominal skin, respectively. 2. After bilaterally sectioning the splanchnic nerves in vagal intact animals, the reflex facilitation of gastric motility produced by hind paw stimulation persisted, but the reflex inhibition previously produced by abdominal skin stimulation disappeared. 3. Hind paw stimulation increased efferent activity of the gastric branch of the vagus nerve, but stimulation of abdominal skin had little influence. 4. Bilateral vagotomy in splanchnic nerve intact animals did not influence the gastric reflex inhibition by abdominal skin stimulation, but either abolished gastric reflex facilitation produced by hind paw stimulation or reversed the reflex facilitation response to slight reflex inhibition. 5. Efferent activity of the gastric sympathetic nerve was greatly increased by abdominal skin stimulation, and was either slightly increased or not influenced by hind paw stimulation. 6. It was concluded that reflex increase of efferent activity of the gastric vagi was responsible for the gastric motility facilitation produced by hind paw stimulation, and also that reflexly increased efferent activity of the gastric sympathetic nerves resulted in gastric motility inhibition produced by abdominal skin stimulation. It is suggested efferents are inhibitory. 7. After spinal transection at the cervical level, the reflex facilitation of gastric motility previously produced by stimulation of a hind paw was completely abolished, or reversed to slight reflex inhibition, while reflex inhibition of gastric motility produced by stimulation of abdominal skin remained. It was concluded that the gastric reflex inhibition was a spinal reflex. 8. Interaction between reflex facilitation and inhibition of gastric motility during simultaneous stimulation of both hind paws and abdominal skin was observed as partial cancellation of each effect by the other. However, sympathetic reflex inhibition of gastric motility seemed to be much stronger than the vagal reflex facilitatory effect.


Calcium channels in the high resistivity axonal membrane of photoreceptors of the giant barnacle.

1. The distribution of calcium channels in the cell membrane of the photoreceptor neurone of the giant barnacle, Balanus nubilus, was studied by recording intracellularly in or near the soma, in the axon, and near the presynaptic terminals. The membrane properties of these different regions of the cell could be studied by separately superfusing each region with test salines or by cutting the axon between two regions. 2. In the presence of tetraethylammonium (TEA) or 3-aminopyridine (3-AP), but not in their absence, Ca dependent action potentials could be evoked with depolarizing current pulses in the somatic, axonal, and terminal regions. Consequently, voltage-sensitive Ca channels and TEA-sensitive channels are present in all three regions of the cell. 3. The action potentials recorded from the three regions were similar in their slow times-to-peak (30-300 msec), long durations (0.2-2 sec in 100 mM-TEA), and long-lasting (0.2-10 sec) undershoots. The action potentials were inhibited by extracellular Co. 4. Clear differences were consistently observed between terminal action potentials and axonal or somatic action potentials in TEA. Terminal action potentials displayed a lower voltage threshold, faster rate of rise, and were less sensitive to inhibition by extracellular cobalt, suggesting that the Ca current is greater in the terminal region. 5. Bathing the receptor axon in low Ca or Co solutions led to a greater attenuation of large depolarizing components of the visual signal as they spread to the presynaptic terminals.


Characteristics of the anion channel in the sino-atrial node cell of the rabbit.

1. The anion permeability of the sino-atrial node cell membranes was determined by substituting various anions for Cl and observing the resultant transient changes in membrane potential. The permeability sequence was found to be in the following order: thiocyanate greater than NO3 greater than I Br greater than Cl greater than acetate. 2. The membrane resistance in Cl solution was compared with that in various anion solutions by the voltage-clamp method. The conductance sequence for the sino-atrial node cell membrane was observed to be the same as the permeability sequence. 3 The potential generated by the Na-K pump was partly short-circuited in normal bathing solution, and thus the pump could be responsible in part for the generation of the sin-atrial node resting membrane potential. 4 When Cl was replaced by acetate, a less permeable ion, the inward-going rectification disappeared. Thus, the inward-going rectification might be due partly to a time- and voltage-dependent Cl current.


Open-circuit sodium and chloride fluxes across isolated opercular epithelia from the teleost Fundulus heteroclitus.

1. The Na+ and Cl- fluxes across opercular epithelia from sea water-adapted Fundulus heteroclitus were measured in vitro under open-circuit conditions while bathed on the mucosa with sea water and the serosa with Ringer solution. 2. The mean predicted Na+ flux ratio was 0.94 +/- 0.08 and the observed ratio was 1.14 +/- 0.12 (n = 15; mean +/- S.E. of mean). The difference in these means was not significant (P greater than 0.20). The mean predicted Cl- flux ratio was 11.4 +/- 0.9 and the mean observed ratio was 1.38 +/- 0.27 (n = 10). The difference in these means was significant (P less than 0.001). 3. Ouabain, at 10(-6) M in the serosal solution, produced a significant (P less than 0.01) reduction in the Na+ efflux while having no significant (P greater than 0.40) effect on the Na+ influx. The agreement between the predicted (1.70 +/- 0.14) and observed (1.72 +/- 0.18) Na+ flux ratios after ouabain treatment suggested that this effect could be completely attributed to the depolarization of the epithelium secondary to ATPase inhibition. 4. beta-adrenergic activation by isoprenaline stimulated the Cl- efflux 24.2% and alpha-adrenergic activation by noradrenaline inhibited the Cl- efflux 66.5%. These changes occurred oppositely to those predicted by the changes in the electrical gradient produced by these agents, while the changes in the Cl- influxes corresponded to the electrical changes. Short-circuit experiments confirmed these effects on the Cl- efflux and the lack of effects on the Cl- influx. 5. The results suggested that Na+ was near theromodynamic equilibrium and that the unidirectional fluxes were passive. The effects of alpha- and beta-adrenergic activation suggested that the active Cl- secretion may be antagonistically regulated by catecholamines.


Potassium depletion and sodium block of potassium currents under hyperpolarization in frog sartorius muscle.

1. A three-electrode voltage clamp method was used to investigate the mechanism of the fall in resting potassium permeability which occurs under extreme hyperpolarization in frog sartorius muscle fibres. 2. Experiments were performed which show that this permeability change is due to a potential dependent block by Na+ ions present in the external solution. 3. Inward K-currents recorded on hyperpolarization turned off exponentially with time. In the presence of Na the steady-state current-voltage relation had a region of negative slope beyond -140 mV. This negative-slope region was removed when Na was replaced by TMA, Tris or Li. Increasing [Na] to 140 mM shifted the negative-slope region to less negative membrane potentials; reducing [Na] to 14 mM shifted the region to more negative potentials. 4. The time constant for the turn-off of the currents (tau) was the same in Na and TMA-containing solutions at  membrane potentials positive to -140 mV. At more negative membrane potentials the tau s in Na became progressively shorter than those in TMA. Increasing [Na] to 140 mM (from 70 mM) gave smaller tau s at all potentials. 5. If fibres were hyperpolarized to -240 mV and then repolarized to -160 mV in 70 mM-Na the current recorded during the second pulse turned on with time, often reaching a value greater than that at the end of the first pulse. This behaviour was removed when Na was replaced by TMA or Tris. 6. An estimate of the steady-state relationship between the degree of block and membrane potential was obtained, and could be fitted by an expression for a potential-dependent ionic block with a very low affinity binding site for Na+ in the membrane. 7. The recovery after hyperpolarization of K-currents at the holding potential was examined in two-pulse experiments. In 70 mM-TMA recovery occurred at the same rate whether the initial hyperpolarization was to -120 or to -210 mV. In 70 mM-Na recovery after an initial pulse to -120 mV occurred at the same rate as in TMA, but recovery after a pulse to -210 mV occurred about 9 times faster. These results are consistent with depletion of K from the lumen of the T-system dominating the turn-off of K currents in TMA and in Na for the hyperpolarization to -120 mV, but a different mechanism being involved for the -120 mV pulse in Na. 8. A three-compartment model is presented which attempts to describe the depletion of K from the T-system. The model accurately predicts the time-course for the decline of inward K-currents, both in 10 and 80 mM-K solutions.


The action of acetylcholine and catecholamines on an intracellular calcium store in the smooth muscle cells of the guinea-pig taenia coli.

1. The role of an intracellular Ca store in excitation-contraction coupling was studied by recording isometric tension development of thin strips (100-150 micron in diameter) of taenia coli incubated in Ca-free solution containing 2 mM-EGTA. 2. The smooth muscle cells of taenia coli do not contract during exposure to a K+-rich and Ca-free solution. However a contractile response can be elicited by acetylcholine or carbachol at concentrations exceeding 10(-6) M. These contractions are probably induced by a release of intracellular Ca. Ca is also released from the same store, although less effectively, by histamine and caffeine. 3. The amount Ca in the intracellular store, as revealed by the magnitude of the carbachol contraction in Ca-free solution, increases after contractions have been induced by high (K+)0 or by solutions containing low concentrations of carbachol. This contraction amplitude decreases after stimulation with a high concentration of carbachol. The amount of Ca in the filled store is sufficient for a near-maximal contraction. 4. The activation of beta-receptors during a K+-depolarization reduces the height of the contracture and induces a carbachol response in Ca-free solution which is higher than that obtained after a preceding K+ depolarization without isoprenaline. This observation indicates that an increased uptake of Ca into the carbachol-sensitive store contributes to the relaxing effect of beta-agonists. 5. In the tissues which have been loaded with 45Ca in a K+-depolarizing solution, a release of Ca into Ca-free solution is observed when the muscle is stimulated with carbachol, but not when it is stimulated with Ca-free high K+. The release is larger when isoprenaline was present during the loading with 45Ca. 6. The removal of Na+ from the solution exerts a complex and unexplained action on the Ca store. Substitution of Na+ by Tris+ and by K+ have similar effects. 7. It is concluded that the smooth muscle cells of the guinea-pig taenia coli have an intracellular store of Ca which participates in excitation-contraction coupling. The store is sensitive to muscarinic agonists, beta-agonists and monovalent ions, but is not affected by depolarization of the outer membrane.


Bicarbonate exchange through the human red cell membrane determined with [14C] bicarbonate.

1. Bicarbonate transport across human red cell membranes was studied between 0 and 10 degrees C at alkaline pH values by determining the efflux of 14C-labelled bicarbonate from resealed erythrocyte ghosts. Transfer of labelled CO2 was eliminated as a source of error, when formation of intracellular 14CO2 was inhibited with carbonic anhydrase inhibitors. The study showed that there are no fundamental differences between the characteristics of bicarbonate and of chloride self-exchange as has been inferred from previous studies of chloride-bicarbonate exchange. 2. Efflux of radioactivity could be reduced more than 99% by reversible and irreversible inhibitors of anion transport. Inhibition of both chloride and bicarbonate self-exchange was linearly related to the binding of 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS) to the membranes. Complete (i.e. greater than 99%) inhibition was obtained after binding of 1.2 x 10(6) DIDS molecules per cell. 3. Bicarbonate self-exchange proved a saturable function of bicarbonate concentration, with a maximum at external and internal concentrations of approximately 100 mM, showing self-depression at higher bicarbonate concentrations, and half-maximum exchange flux at a concentration of 10 mM. The results were consistent with the hypothesis that the exchange mechanism has two anion binding sites, one mediating ion transport and the other causing transport inhibition. 4. Maximum exchange flux of bicarbonate was about 30% larger thant that of chloride, and the affinity of bicarbonate for the transport site was about three times larger than that of chloride. The apparent activation energy of bicarbonate exchange was 28 kcal/mole, the same order of magnitude as found for other inorganic anions between 0 and 10 degrees C. 5. The ability of other inorganic anions to exchange with bicarbonate decreased in the sequence Cl greater than NO3 greater than F greater than Br greater than or equal to I, corresponding to the sequence of the rate of self-exchange of halides. 6. Counter-transport of bicarbonate could be driven by a chloride gradient, when ghosts containing KCl were suspended in a medium containing traces of labelled bicarbonate in addition to a non-permeating anion. Concentration ratios (ci/co) up to about 1000 could be obtained. 7. It is concluded that bicarbonate is transported by the inorganic anion exchange mechanism of the erythrocyte membrane. The slight differences between the exchange kinetics of chloride and bicarbonate were explained by differing affinities of the two anions for the two anion binding sites of the transport system.


Hypothalamic thermo-responsive neurones in the new-born rat.

1. Single unit activities were recorded from the neurones in the preoptic area and anterior hypothalamus of developing new-born rats (aged 1-24 days old) during thermal stimulation of the brain. During the first 2 weeks of life, about 80% of these neurones had low spontaneous firing rates between 0.1 and 5 impulses/sec at 38 degrees C hypothalamic temperature (Thyp). 2. Out of 640 units studied, 118 units increased the firing rate upon elevation of Thyp (warm-units) and fourteen showed the opposite type of response to temperature changes (cold-units). Warm-units were found in the rats of all the age span studied and cold-units were recorded in the rats more than 8 days old. 3. Thermal coefficients of warm-units and cold-units varied between +0.11 and +2.47 and between -0.10 and -0.49 impulses/sec, degrees C, respectively. Number of warm-units with higher rates of firing and greater thermal coefficients, comparable to those of warm-units in the adult, gradually increased with growth. The thermal responsiveness of warm-units, when expressed by Q10, are already high even in the immediate neonatal period. Their Q10 values were in the range between 2 and 38.5 (mean 6.4). 4. Units responding to extrahypothalamic temperatures were only found in the rats more than 14 days old. 5. All the six warm-units tested increased the firing rates following subcutaneous injections of capsaicin, while the majority of thermo-unresponsive units were not affected by this drug. 6. It is suggested that thermo-responsive neurones in the preoptic area and anterior hypothalamus in the new-born rat have attained some degree of electrophysiological maturity, despite their slowly firing characteristics.


Effects of dark adaptation on spatial and temporal properties of receptive fields in cat lateral geniculate nucleus.

1. We studied the effect of dark adaptation on the spatial organization of receptive fields of single cells in the lateral geniculate nucleus l.g.n. of the cat. 2. Contrary to previous reports, we found that in many l.g.n. cells the ability of the receptive field surround to suppress the response of the centre was diminished following dark adaptation. 3. The degree of reduction of the surround antagonistic strength varied from cell to cell, and was independent of the various classifications of visual neurones (X/Y, ON/OFF, layer, A/layer, A1 and central/peripheral). 4. Most cells also showed an increase in the apparent size of the excitatory centre upon dark adaptation. On the average, the width of the most effective bar stimulus located at the centre of the receptive field increased more than twofold. 5. We also studied the effect of dark adaptation on the temporal properties of l.g.n. receptive fields. In many cells dark adaptation changed the temporal modulation transfer function: it flattened the amplitude function, and changed the phase relationship between the centre response and the surround response. 6. Retinal ganglion cells showed qualitatively similar behaviour to that of l.g.n. neurones. 7. Our data do not support the notion that retinal ganglion cell centres converge on l.g.n. cells to form their surround mechanism.


Development of spinal reflexes in the rat fetus studied in vitro.

1. The onset and development of spinal reflex activity was investigated using the isolated spinal cord of the rat fetus. The potential changes generated in motoneurones were recorded extracellularly from L3 ventral roots. 2. A spike potential was recorded from the ventral root at embryonic day 13.5 in response to stimulation of the cord surface close to the ventral root. The discharge persisted in Ca2+-free solution but was blocked by tetrodotoxin. 3. At embryonic day 14.5, trans-synaptically evoked discharges were detected in motoneurones. 4. Stimulation of the dorsal root was first effective in eliciting reflex discharges at embryonic day 15.5. The reflex response then consisted of a prolonged depolarization upon which were superimposed small spikes, and was probably polysynaptic. 5. A spike potential, presumably a monosynaptic reflex, was generated at the end of fetal life. This discharge appeared first at embryonic day 17.5 in a primitive form. 6. Between embryonic day 16.5 and 17.5, stimulation of the dorsal root of diffferent segments (L1-L6) elicited responses similar to those induced by the corresponding (i.e. L3) dorsal root stimulation. These inter-segmentally induced responses were then reduced in size toward the birth. However, in the presence of strychnine, a train of spike discharges of similar shape to the segmentally induced response was also evoked by stimulation of the dorsal root at L4 or L5. These spikes disappeared during further post-natal development. 7. It is concluded that synapses in the segmental polysynaptic pathway become functional in a retrograde sequence with respect to the direction of normal reflex impulse flow. The reflex responses, elicited by stimulation of the dorsal roots of different segments, are suggested to be suppressed first by the development of inhibitory mechanisms and then by neuronal cell death or by elimination of the synapses responsible for generating the inter-segmental reflexes.


Effects of acetylcholine and catecholamines on the smooth muscle cell of the porcine coronary artery.

The effects of acetylcholine (ACh), noradrenaline (NA) and isoprenaline (Isop) on the membrane and mechanical properties of smooth muscle cells of the pig coronary artery were investigated by micro-electrode, double sucrose gap and isometric tension recording methods. (1) The mean membrane potential was -51.4 mV and the membrane was electrically quiescent. Application of outward current pulse generated a graded response. The current-voltage relationship was linear for application of inward current pulses. The length constant of the tissue was 0.67 mm and time constant of the membrane was 290 msec. The tissue possessed cable-like properties. (2) ACh (10(-10) to 10(-5) g/ml.) did not change the membrane potential and membrane resistance, but NA and Isop hyperpolarized the membrane and reduced the membrane resistance. These actions of catecholamines, presumably mediated by beta-adrenergic receptors, were suppressed by propranolol but not phentolamine. (3) The minimum depolarization required to produce the contraction was 4 mV by excess extracellular K concentration and 6 mV by electrical displacement of the membrane potential. The amplitude of the contraction evoked by depolarization in excess K was consistently larger than that by the electrical displacement. The minimum concentration required to produce the contraction induced by ACh was 5 x 10(-9) g/ml. NA and Isop consistently suppressed the contraction evoked by excess extracellular K or by ACh. (4) When the tissue was immersed in Ca-free EGTA solution containing excess K or Ca-free EGTA Krebs solution, the time taken for Ca depletion from the intracellular store site was longer with depolarized membranes than that with polarized membranes. ACh evoked contraction, even after the tissue had lost the ability to produce contraction by excess extracellular K in Ca-free solution. (5) After the tissue had been immersed in Ca-free solution containing excess K for more than 4 hr, or Ca-free Krebs solution for more than 2 hr, application of Ca evoked the contraction. These effects of Ca were suppressed by application of catecholamines. The amplitudes of subsequent ACh-induced contraction in Ca-free excess K were not suppressed, while there was a suppression of the K-induced contraction in Ca-free Krebs solution. (6) It is concluded that the smooth muscle cell of the pig coronary artery possesses muscarinic and beta-adrenergic receptors. The former mainly activates the mechanical response without affecting the surface membrane while the latter modifies both membrane and mechanical properties.


Time- and voltage-dependent ionic components of the rod response.

1. The electrical properties of individual rods, physically isolated from the rod network, were measured in terms of the time course of response and voltage-current relations derived from current steps. Properties were measured in normal and altered bathing media designed to reveal the ionic basis for the time and voltage dependent properties of the rod response. 2. In normal media the rod membrane was strongly outward-rectifying with slope resistance near 100 M omega when hyperpolarized, but near 10 M omega when depolarized from a typical ambient level near 35 mV. The membrane become inward rectifying for hyperpolarizations beyond -95 mV, with slope resistance near 70 M omega. 3. The normal hyperpolarizing overshoot associated with the rod response was strongly potential dependent: the overshoot in response to a current step disappeared when the membrane was first depolarized or hyperpolarized by more than about 10 mV from the -35 mV ambient potential level. The decay from overshoot elicited either by current or light, could be approximated with a first order time constant of about 150 msec. 4. In the absence of sodium the peak-plateau sequence remained intact. Membrane resistance increased during transition to the plateau. The plateau became more hyperpolarized than the early phase during responses beyond -75 mV. These results indicate a time- and voltage-dependent conductance other than sodium contributes to the peak-plateau response, probably potassium. 5. Outward rectification was greatly reduced in the presence of 15 mM-TEA,  suggesting that it is mediated by potassium activation. 6. Inward rectification, and the associated transients near -95 mV were eliminated in the presence of 2 mM-caesium, suggesting that potassium conductance contributes to the time and voltage dependent inward rectification.


Intercellular spaces in chemically fixed corneal endothelia are related to solute pump activity not to solvent coupling.

1. Stereological analyses of the lateral intercellular spaces in the endothelium of rabbit corneas after chemical fixation were undertaken. 2. Immediately preceding chemical fixation the endothelia were in one of four transport modes: (a) bicarbonate pump activated and no coupled solvent flux, (b) bicarbonate pump activated and, coupled to it, a solvent flux, (c) no fluxes across the endothelia and (d) passive fluid fluxes across the endothelia. 3. In each transport mode, the intercellular spaces were measured after immersion in a series of fixatives in which the concentration of buffer (sodium cacodylate) was increased. 4. Lateral intercellular spaces were a function of buffer concentration in the fixative and activity of the bicarbonate pump. They were not a function of either solvent coupling or passive solvent flow. 5. It is concluded that the characteristic changes of lateral intercellular spaces, when transport is inhibited, do not indicate the site of local osmotic coupling.


Inhibition by angiotensin II of baroreceptor-evoked activity in cardiac vagal efferent nerves in the dog.

1. Action potentials were recorded in single baroreceptor fibres dissected from the carotid sinus nerves in dogs during increases in blood pressure caused by I.V. injection of angiotensin II, and by I.V. injection of phenylephrine or inflation of an aortic balloon. Action potentials were recorded in single cardiac efferent fibres dissected from the right cervical vagus nerve in other dogs during increases in blood pressure caused by angiotensin II, and by phenylephrine or by inflation of an aortic balloon. 2. There was no difference in the discharge frequency of single carotid sinus baroreceptor fibres at any blood pressure when phenylephrine, balloon inflation, or angiotensin II were used to raise the pressure. 3. Activity in single cardiac vagal efferent fibres was increased when blood pressure was increased by phenylephrine or by inflation of an aortic balloon. However, when blood pressure rose by a comparable amount in response to angiotensin II, vagal firing decreased (three fibres), was little changed from control levels (four fibres), or increased less than it did in response to phenylephrine (one fibre). 4. It is concluded that while angiotensin II has no effect on baroreceptor sensitivity, it does inhibit vagal discharge which is evoked by stimulation of arterial baroreceptors.


Distribution of inulin, sucrose and mannitol in rat brain cortex slices following in vivo or in vitro equilibration.

1. The distribution spaces of inulin, sucrose and mannitol in rat brain cortex slices were determined in tracer experiments. Tracer equilibration times of 5 hr were used with combined ventriculo-cisternal perfusion and I.V. infusion of tracers. After 5 hr of equilibration the distribution volumes (expressed as mul./100 mg wet wt.) obtained using the perfusion fluid as reference and after correction of tracer amount in residual blood were obtained. Information on cellular uptake was obtained by examining a slow component of wash-out curves from brain slices after in vivo equilibration. Distribution spaces were corrected for intracellular penetration to obtain the extracellular volumes of distribution. Inulin was found to equilibrate with 13.3 mul. extracellular tissue water per 100 mg initial wet weight, sucrose with 16.6 mul. and mannitol with 19.5 mul.2. Marker spaces in rat brain cortex slices were also analysed by compartmental analysis of efflux of tracer inulin, sucrose and mannitol following in vitro incubation in a balanced medium for 60 min. Following in vitro equilibration, inulin was found to equilibrate with 22.4 mul. extracellular tissue water per 100 mg of final wet weight, sucrose to equilibrate with 31.7 mul. extracellular tissue water and mannitol with 42.3 mul.3. Inulin space in vitro when allowance is made for swelling produced during incubation of the slice was similar to the chemically delineated extracellular distribution volume in vivo. Sucrose and mannitol spaces in vitro, however, did not accord with in vivo determinations, most likely due to access of markers to areas of cell damage in the slice arisen during incubation.4. Comparison of fluid spaces delineated by inulin in slices of rat cerebral cortex following in vivo and in vitro equilibration indicated that swelling produced during incubation in vitro mainly occurred in the extracellular space. Swollen glial cells may account for the small, but significant intracellular swelling in incubated slices.


The electrosensitivity of the lateral line of the European eel, Anguilla anguilla L.

The lateral line neuromast of the eel (Anguilla anguilla) are slightly sensitive to electric current (threshold current density about 1 x 10(-6) A/cm2). A comparison is made with threshold values found by several authors by means of conditioning experiments.


Functioning of catfish electroreceptors: relation between skin potential and receptor activity.

Properties of catfish electroceptors were investigated by simultaneous recording of the skin potential and the activity of an afferent nerve. 1. The normal threshold stimulus intensity induces a potential amplitude of about 10 to 30 muV across the skin (Table I). 2. The average spike frequency in the nerve increases approximately with the logarithm of the stimulus intensity (Fig. 1). 3. The direct current restoring the receptor activity in calcium deficient media makes the skin potential more negative. 4. Presumably, not the skin potential itself but a difference between the skin potential and the e.m.f. generated by the receptor epithelium influences receptor functioning. 5. Amplitude and phase characteristics can be described by a filter circuit (Fig. 4 and 5).


Marine electric fields and fish orientation.

1. Two methods for short-span measurements of DC electric fields in the sea are described. 2. The results indicate a difference between local electric fields (up to 150 muV/m) caused by bottom structures and regional electric fields (up to 60 muV/m) due to electromagnetic processes. 3. The possible relevance of these phenomena to electro-sensitive fishes is discussed.


Spatial aspects of electrolocation in the mormyrid fish, Gnathonemus petersii.

The range of electrolocation in the weakly electric fish, Gnathonemus petersii, was determined for plastic and aluminium cubes. A characteristic change in the fish's EOD activity, and abrupt change to more uniform EOD intervals (regularization), was used as the criterion for object detection. The average response distances extending laterally from the fish's longitudinal axis were significantly different (p less than 0.05) for the aluminium cube (5.4 cm) and the plastic cube (7.0 cm).


Development of the gigantocerebellum of the weakly electric fish Pollimyrus.

The morphogenesis of the "hypertrophied" mormyrid cerebellum was investigated in Pollimyrus (Pisces). Two adults and 36 larvae and young fish raised in captivity were used. Two Gnathonemus petersii adults were taken for comparison. The ontogenetic development of the various cerebellar structures was analysed in inverse chronological order with the aid of serial sagittal and frontal brain sections. Special attention was given to the trilobed corpus cerebelli (C1, C2, C3), the lobi transitorii et caudales, the valvula, the crista cerebelli, the eminentia granularis and the lobus lineae lateralis. 1. The cerebellar structures are of bilateral origin; they develop from the cerebellar and acoustico-lateral "anlage" of the rhombencephalon behind the rhombomesencephalic fissure, either through budding or individualisation and appear between the 4th and 11th day after spawning. The midline fusion of the symmetrical structures is accomplished somewhat later, between the 8th and 23rd days. 2. The cerebellar structures acquire their definitive spatial organisation within 38 days, except for the valvula whose development takes much longer. Recognisable from the 11th day, the valvula upon which ridges are visible from the beginning continues to grow after the 38th day beyond the mesencephalic ventricle, finally overlying the telencephalon frontally and the different rhombencephalic structures caudally. This development, which includes a large antero-lateral folding of the valvula, takes 240 days. 3. Cytological differentiation is just as complex as the general development of the cerebellar structures. Cortical stratification first begins on the 8th to the 11th day in the corpus cerebelli and in the valvula from day 21 to 23 onwards. This differentiation is characterised throughout almost the entire cerebellum by a downward migration of the superficial undifferentiated cells which then constitute the granular layer. In the valvula, the majority of the undifferentiated cells leave the ridges to form a continuous granular layer at the base of the ridges. 4. A differentiation gradient was observed on the antero-posterior axis. 5. In spite of its complexity, the mormyrid cerebellum develops much more rapidly than the cerebellum of the trout.


Processing of ampullary input in the brain: comparison of sensitivity and evoked responses among elasmobranch and siluriform fishes.

1. Averaged evoked potentials (AEP) in response to pulses and sine waves of electric current, either as a homogeneous field or a large dipole field around the fish, have been recorded from the brain in 5 genera of elasmobranchs and 10 genera of siluriform fishes. 2. In the elasmobranchs, AEP's and spike-hash bursts are described from medulla, cerebellum, mesencephalon and telencephalon. A complex  sequence of early and late waves is found in each level. Two sets of factors influence the latency and amplitude of the component waves. One is stimulus parameters including intensity, stimulus orientation, sign of the change of current, position of dipole, serial number in the first few cycles of a train as well as interval or frequency of a regular series. Separate component peaks of the complex AEP appear to have different dependencies upon these factors. To sinusoidal stimuli the best response by a certain criterion is at 20--30 Hz in a shark (Carcharhinus), 10--15 Hz in a ray (Potamotrygon); these are much higher than the values based on behavior from previous authors. The lowest threshold, with moderate averaging, was 0.015 muV/cm (= 0.8 nA/cm2) in marine species, less than 50 muV/cm (= 0.7 nA/cm2) in the freshwater ray. 3. The other set of factors determining AEP is brain parameters, including the recording locus, the type of electrode and electrode advance and the state of the brain (anesthesia, etc.). There is evidence of topographic segregation of some stimulus parameters, but mapping was not undertaken. Responsive regions are described in the several brain levels. 4. The best loci for electric AEP are distinct from those for acoustic and photic AEPs. No interaction between these was found. 5. All of the siluriforms tested show electroreception by the criterion of high sensitivity AEP. No obvious specialization was noted among the diverse species, but most were represented by a single experiment. Taken together with the previously known species, the sample of nine families of this large order suggests that this is a general characteristic of the order. 6. The best responses were found in the region of the torus semicircularis and in the lateral lobe. The lowest threshold by the criterion used was less than 0.15 mV/cm (= 2 nA/cm2), but some were nearly 2 mV/cm. Compared to much lower values in Ictalurus, this suggests species differences although part of the difference may be due to failure to record from the optimal locus. The AEP may be useful as a method of suveying for other electroreceptive groups. It is also potentially useful to reveal discriminable parameters of importance, such as dipole position, orientation, polarity and frequency.


Electrosensory systems in the mormyrid fish, Gnathonemus petersii : special emphasis on the fast conducting pathway.

1. Rhombencephalic and mesencephalic structures involved in electroreception were investigated by electrophysiological methods in the weakly electric fish Gnathonemus petersii. 2. The existence of a synchronous response to electric field stimulation of the fish in the mesencephalic exterolateral nucleus (n.ext.-lat.mes) with 2.5-3 ms latency was confirmed. The lateral line lobe nucleus (nLLL) is identified as the rhombencephalic relay for the mesencephalic responses because of the short latency synchronous response in the nLLL obtained by threshold stimulation of the posterior lateral line nerve. Responses in both the nLLL and the n.ext.-lat.mes. appear and their amplitudes increase simultaneously with increasing stimulus intensity. 3. Comparison of latencies supports a three-neuron pathway hypothesis which also agrees well with the various functional properties described. 4. The nLLL-n.ext.-lat.mes. pathway is blocked sharply for a period of 1 ms occurring 3 ms after the electric organ discharge (EOD). This inhibitory period is phase-related to the Mesencephalic Command Associated Signal (MCAS) of Aljure (1946) ; The phase relation is such that no response is observed to the fish's own EOD. 5. Long-lasting responses of 10-12 ms duration to higher stimulation intensities were obtained in the ganglionic layer of the lateral line lobe (LLL). Intensities evoking maximal responses in the nLLL and n.ext.lat.mes. are still threshold stimulation for lateral line lobe responses. 6. Long-lasting responses (of the same order as in the LLL) to the fish' own EOD were observed in the mesencephalic lateral nucleus. Responses to artificial electric pulses were obtained only if delivered in a certain phase realtion to the MCAS. The MCAS displays a facilitating effect on the slow conducting electrosensory system. 7. Results indicate the existence in mormyrids of a double, fast and slow conducting, electrosensory system similar to that of gymnotid fish. The mormyrids can control both of these electrosensory systems by means of the MCAS, the effect of which is opposite for the same time period on the two systems.


Single unit activity in the mesencephalon of Sternarchus.

Action potentials evoked in a phase-locked 1 : 1 relationship by natural electric organ discharges (EOD) were recorded extracellularly and intracellularly from single mesencephalic magnocellular nucleus units in the high frequency electric fish Sternarchus albifrons (Gymnotidae). This activity has been shown to be the result of an extrinsic feedback of the electrosensory system and is probably important for the socalled jamming avoidance response triggered artificial electric pulses when delivered into the water in a 1 : 1 relationship at intensities higher than the EOD. In the same way, artificial pulses of frequency near EOD could either drive or, due to beats, greatly disturb the regular firing of the units. More insight into the neural mechanism was yielded by single EOD-triggered shocks provoking a failure in firing of certain action potentials of the series and causing long-lasting (10-20 ms) accelerations and decelerations of the regular EOD-evoked firing (transient disturbance). Intracellular stimulations show similar effects. The biological significance of this neural mechanism for the fish's electroperception and JAR is discussed.


On the electromotor neurons of both electric organs of Pollimyrus isidori (Mormyridae, Teleostei).

The electromotor neurons (EMNs) of the adult electric organ of Pollimyrus isidori and the "giant neurons" (GNs) found in the more rostral part of the spinal cord were investigated both with light and electron microscopical methods. The two kinds of neuron are more or less similar in size, about 30 microns, and are found in the more dorsal part of the spinal cord. The EMNs show somatosomatic gap junctions, as do the GNs. In addition, chemical synapses could be found between nerve fibres and both types of neurons. Histochemical investigations show that the EMNs and the GNs are both AChE positive. On the basis of the arguments presented in the discussion, we believe that the "giant neurons" are the electromotor neurons of the larval electric organ of Pollimyrus isidori.


Sex-role identity, parental identification, and self-concept of adolescent daughters from mother-absent, father-absent, and intact families.

The effects of divorce and resulting paternal or maternal absence on the sex-role identity, parental identification, and self-concept of 39 adolescent daughters were investigated. Differences among the mean sex-role identity scores and self-concept scores of the daughters of mother-absent (MA), father-absent (FA), and intact (IF) families were not found. Parental identification with the mother and the father in the IF group was greater than identification with the mother in the FA group. Fathers in the MA and IF groups did not differ on the sex-role identity measure; FA and IF mothers also did not differ on this measure. The sex-role identity scores of the daughters were not related to the sex-role identity scores of either their mothers or fathers. The results revealed no negative consequences of the father receiving custody of an adolescent daughter and, therefore, suggest that fathers of adolescent daughters should be given greater consideration in custody cases.


Impulsivity, temporal perspective, and posthospital adjustment of neuropsychiatric patients.

Hypotheses were tested regarding relationships between impulsivity as a personality construct and various biographical characteristics among neuropsychiatric patients referred for rehabilitation. Seventy-five males and five females (mean age 33) with mixed diagnoses served as Ss. Variables included an ego-delay measure obtained from temporal estimations, perceptions of temporal dominance and relatedness obtained from Cottle's Circles Test, Ss' ages, and a measure of long-term posthospital adjustment. Ego-delaying patients were significantly younger, diminished the importance of their past temporal mode relative to the present and future, perceived the future as a dominant temporal mode relative to the present and past, and achieved significantly better long-term adjustment following psychiatric hospitalization.


The development of embarrassment.

Parents of children in the age range 3 to 12 years were asked about their children's embarrassment and blushing during the previous six months. This survey revealed that roughly one in four preschool children showed embarrassment. Starting with age 5, a majority of children showed embarrassment. There were no systematic gender differences. Blushing was reported in slightly more than half the children who were embarrassed. On the assumption that embarrassment signals the presence of a social self, a social self develops at about 5 years of age for most children.


Sex-role behavior change: intrasubject studies of boyhood gender disturbance.

Sex-role behaviors were modified in a seven-year-old boy who had been evaluated by an independent psychiatrist as manifesting cross-gender identification. The child's developmental history paralleled the retrospective reports of adult transsexuals. In Experiment 1, the boy was treated in the clinic by a nonprofessional female "therapist" who reinforced "masculine" sex-typed play behaviors and extinguished "feminine" behaviors. The treatment effects generalized to the boy's play with a different set of toys in the presence of male and female strangers, but did not generalize to the boy's play in the alone condition. An intrasubject reversal design was used to replicate the treatment effects. Concurrently, Experiment 2 was conducted to shape the child's athletic skills to a level that would enable him to compete with his peers. The treatment effect for "sockball" was replicated for "kickball" in a multiple-baseline intrasubject design. Future research is suggested to explore variables that would maximize both generalization of treatment effects and parental cooperation over time.


Predictive analysis vs. segmentational analysis in sentence perception.

Three experiments involving ongoing sentence perception are described. A nonword detection (NWD) latency procedure was employed without a concurrent task (Experiment I), with a concurrent comprehension task (Experiment II), and with a concurrent recall task (Experiment III). Predictions were made based on two plausible models of sentence perception--predictive analysis (PA) and segmentational analysis (SA). Both characterize the hearer as actively imposing a grammatical structure on the input. PA constructs a surface structure representation sequentially (i.e., on a word-by-word basis). SA partitions off clauselike units before establishing the structure of smaller within-clause constitutents. The NWD latency data generally support a PA system (particularly when a concurrent task is used). The results of a nongrammatical condition in Experiment III confirmed that the general findings were not artifactual.


"Motority" in three functional domains of word meaning.

This article deals with relations between "mental motor" evoking capacity ("motority," Putnoky, 1975a, b) and the sensory and affective connotations, as well as certain denotations, of words. Sensory connotation is indexed by degree of visual, auditory, and tactual imagery, as assessed on a 7-point scale, while affective connotation is indexed by the usual three factors tapped by the semantic differential. The aspect of denotation used here is the abstractness value of words, also based on rating by scales. The general conclusions about motority are as follows: (1) the finding that its sensory connotations are mainly via the auditory modality of imagery, and especially in correlation with abstract words, suggests that it has a specific function that may have originated in the processing of heard language; (2) it correlates with the potency and activity factors of affective connation, which suggests the existence of a nonspecific function or component in it; (3) correlations with abstractness reflect that motority must have a denotative function or component, especially in case of abstract verbal stimuli. On the basis of the results, motority is supposed to play a regulative role at higher levels of the organization of word meaning in particular.


Interaction of visual information, verbal information, and linguistic competence in the preschool-aged child.

Carol Chomsky found evidence to support the notion that children have not mastered the syntactic form of the sentence "John is easy to see" until after the age of 8 years. However, she failed to control for the effects the visual stimulus might have had on the child's understanding of the stimulus question. This study reexamined Chomsky's conclusions by using two experimental conditions. The first condition was an exact replication of Chomsky's method, while the second included a control for the biasing effects produced by the visual stimulus. The results confirmed the authors' suspicions that the visual stimulus was indeed distorting Chomsky's findings and that, on the average, children were able to decode this particular syntactic form by the age of 67 months. These findings are discussed from the perspective of Bruner's theory, which states that cognitive processes of children under 8 years of age are dominated by the iconic mode of representation.


Ultrastructural evidence for phagocytosis of spermatozoa in the bovine rete testis and testicular straight tubules.

Ultrastructural examination showed that the epithelium of the bovine rete testis and the tubuli recti could phagocytose spermatozoa. Macrophages were regularly found in the basal parts of the epithelial cells and could be involved in the removal of degraded sperm material.


Influence of hCG injection and steroid treatment on prostaglandin metabolism by rabbit uterus and oviduct.

Metabolism of PGE-2 and PGF-2 alpha by cytosolic fractions (100 000 g supernatant) of rabbit uterus, oviduct and lung was measured in vitro. Metabolism of PGE-2 was greater than that of PGF-2 alpha for oviduct and uterus. After an ovulating injection of hCG metabolism of both PGE-2 and PGF-2 alpha by lung and uterus declined linearly up to 72 h (during the time of ovum transport). The amount of PG metabolism by the oviduct did not change significantly during this period, but the percentage changes of PGE-2 and PGF-2 alpha metabolism from oestrous values did differ, and perhaps indicated a change in the ratio of intracellular PGs. No change of metabolism of either PG by lung, uterus or oviduct occurred at 24 or 72 h after an injection of 250 micrograms oestradiol cyclopentylpropionate given concomitantly with the hCG (a treatment regimen which causes 'tube-locking' of ova). However, progesterone treatment, in a regimen known to cause accelerated transport of ova through the oviduct, caused significantly enhanced metabolism of both PGE-2 and PGF-2 alpha by uterus and oviduct, but not lung, 30 and 48 h later except for PGE-2 by uterus at 30 h. These results suggest that changes in metabolism of PGE-2 and PGF-2 alpha by the oviduct may be involved in the mechanisms controlling ovum transport.


Age-related changes in the testicular and antler cycles of reindeer, Rangifer tarandus.

A total of 111 male reindeer of various ages was shot in all months of the year to study the relationship between the seasonal changes in testicular activity and the antler cycle. From the changes in testis weight, seminiferous tubular tissue area and plasma testosterone values and the occurrence of spermatogenesis, it is concluded that calves attain physiological puberty in their first year, during which they also complete an antler cycle. The amplitude of the cyclical change in testis weight and plasma testosterone values increases with age and can be correlated with the earlier onset of events in the spermatogenic and antler cycles of older animals. The duration of the spermatogenic and testosterone cycles of reindeer is short, and is inversely related to the long period spent without antlers. It is suggested that testosterone strongly influences the antler cycle of reindeer males.


Growth of the corpus luteum and its progesterone content during pregnancy in the tammar wallaby, Macropus eugenii.

Corpora lutea were obtained from wallabies at different stages of pregnancy, following removal of pouch young to initiate embryonic development. Progesterone was present at a concentration of 11.3 ng/mg in quiescent corpora lutea from lactating animals. Progesterone values rose with increasing corpus luteum weight to reach a maximum of 40--50 ng/mg in corpora lutea weighing 50--60 mg. Total progesterone reached a maximum of 1500 +/- 300 (s.e.m.) ng at Days 21--23 after removal of pouch young, but fell markedly at Days 24 and 25 (900 +/- 150 ng) immediately before parturition.


Exchange of krypton-85 between the blood vessels of the human uterine adnexa.

A miniature Geiger-Müller probe was inserted into one ovary of 8 women undergoing hysterectomy. A control probe was inserted into the other ovary of 2 of the women. Krypton-85 in 0.15 M-NaCl was infused into the adjacent utero-ovarian vein and the radioactivity was registered for 5--14 min after the infusion. An increase of radioactivity was recorded in the ovary in 5 cases. In one of the women with 2 probes, no increase in radioactivity was observed in the control ovary. The results show a local transfer of gas from the ovarian branch of the uterine vein into the adjacent ovary, which may be due to a countercurrent exchange mechanism between the vessels of the human uterine adnexa.


Age-related changes in conversion of  5 alpha-androstan-17 beta-ol-3-one to 5 alpha-androstane-3 alpha,17 beta-diol and 5 alpha-androstane-3 beta,17 beta-diol by rat testicular cells in vitro.

Conversion of labelled 5 alpha-androstane-17 beta-ol-3-one (DHT) by isolated testicular cells from rats of different ages was examined under saturating substrate conditions in vitro (5--10 micrograms DHT/ml in a 24 h incubation). Two detectable metabolites of DHT were produced by testicular cells in vitro. 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-diol) and 5 alpha-androstane-3 beta, 17 beta-diol (3 beta-diol). Production of these diols during a 24 h period was linear, and the amounts formed were directly related to the cell number. The amount of 3 alpha- and 3 beta-diols formed by testicular cells of rats of different ages increased from Day 10 to Day 25, then declined. Testicular cells from rats 10 to 20 days of age converted DHT mainly to 3 alpha-diol, but thereafter 3 beta-diol was the predominant testicular metabolite of DHT.


Nuclear and mitochondrial DNA-dependent RNA polymerases in bovine spermatozoa.

DNA-dependent RNA polymerases have been solubilized from separated head and tail fractions from normal bovine spermatozoa and from spermatozoa carrying the 'decapitated sperm defect'. When enzyme extracts from separated heads and tails were chromatographed on DEAE-Sephadex, the head fraction was resolved into 2 distinguishable peaks eluting at about 0.11 and 0.15 M-(NH4)2SO4 while the tail fraction yielded 4 distinct peaks eluting at about 0.11, 0.15, 0.255 and 0.35 M-(NH4)2SO4. Results indentical to those observed for sperm tails were obtained with extracts prepared from highly purified mitochondria from bovine or murine heart or liver. Optimization of reaction parameters and inhibitor studies with alpha-amanitin and rifampicin revealed strong similarities between eucaryotic nuclear RNA polymerases 1 and 2 and the 2 RNA polymerases associated with sperm heads. Similar experiments comparing the RNA polymerases from somatic mitochondria and sperm tails suggested the sperm tail enzymes were mitochondrial in origin.


Modulatory effects of the amygdala on oestrogen-induced LH secretion in ovariectomized rats.

An increase in LH secretion was induced in ovariectomized oestradiol benzoate-primed rats 5 h after a second injection of oestradiol benzoate. Lesions stereotaxically placed in the cortical and basomedial amygdala of steroid-primed rats abolished this rise. The results provide evidence for a facilitatory action of the amygdala upon LH release and an involvement of this region of the limbic system in oestrogen-feedback mechanisms.


The reproductive tract of the male spiny mouse (Acomys cahirinus) and coagulation studies with other species.

The testes of the spiny mice showed asymmetry, the left being significantly heavier than the right (P = 0.025). Histological studies indicated that spermatozoa were first present in the testes of animals 35--45 days of age but the maturation of the accessory glands, especially the lateral prostates and coagulating glands, occurred later. The highest fructose concentration in the adult was in the lateral prostates (126.97 +/- 22.23 mg fructose/100 g, n = 5) and coagulating glands (99.38 +/- 17.65 mg fructose/100 g gland weight, n = 5). Coagulation tests of mixtures of extracts of seminal vesicles and coagulating glands from spiny mice and rats indicated that the vesiculase of the spiny mouse was active on rat substrates and vice versa. Cross-reactions of extracts of house mouse (Mus musculus), hamster (Mesocricetus auratus), gerbil (Meriones unguiculatus), and guinea-pig (Cavia porcellus) seminal vesicles (substrate) and coagulating glands (vesiculase) with those of rats and spiny mice showed that although the substrates of rat and spiny mouse were readily coagulated by vesiculase from all the other species, rat and spiny mouse vesiculase were not equally active on substrates of the other species.


Lipid changes in boar spermatozoa during epididymal maturation with some observations on the flow and composition of boar rete testis fluid.

The flow rate and composition of boar rete testis fluid were similar to those in other species studied previously. The total phospholipid phosphorus and phospholipid fatty acid content of boar spermatozoa decreased during maturation in the epididymis but the level of phospholipid phosphorus was slightly higher in ejaculated spermatozoa than in epididymal spermatozoa. During passage of the spermatozoa from the testis to the cauda epididymidis, loss of the major saturated acids (palmitic, 16:0, and stearic, 18:0) was extensive but partly recovered in the ejaculated spermatozoa. The mass of docosapentaenoic (22:5) and docosahexaenoic (22:6) acids tended to decrease continuously during maturation but the percentage of 22:6 by weight of total phospholipid fatty acid reached a maximum in the epididymis. Ejaculated boar spermatozoa contained considerably more phospholipid and phospholipid fatty acid than did ejaculated bull or ram spermatozoa.


Lipid changes during epididymal maturation in ram spermatozoa collected at different times of the year.

The phospholipid and phospholipid fatty acid content of ram spermatozoa decreased during maturation in the epididymis but interpretation of the results was complicated by a possible seasonal factor. Loss of individual fatty acids was selective, resulting in an increase in unsaturation during maturation. Testicular spermatozoa and fluid collected directly into chloroform-methanol contained about 7 times more neutral lipid fatty acid than testicular spermatozoa collected for 6--18 h, separated from the rete testis fluid and then extracted; the difference was not due to lipid in the rete testis fluid. Thin-layer chromatography indicated that cholesterol esters and triglycerides were the neutral lipids which were not lost during collection. Epididymal spermatozoa contained only slightly less neutral lipid fatty acid than continuously collected testicular spermatozoa.


Glycolytic, Krebs cycle and pentose phosphate cycle enzymes in spermatozoa of the buffalo (Bubalus bubalis).

Various enzymes of glycolysis (hexokinase, phosphoglucoisomerase, aldolase and lactate dehydrogenase), the Krebs cycle (isocitrate, succinic and malate dehydrogenases), and the pentose phosphate cycle (glucose-6-phosphate and 6-phosphogluconate dehydrogenases) were studied in buffalo spermatozoa by biochemical and cytochemical methods. The enzymes of glycolysis were found to be loosely bound whereas those of the Krebs and pentose phosphate cycles were strongly bound to mitochondrial membranes. All the enzymes studied were localized histochemically in the mid-piece.


Can reduced consumption of gonadotrophins account for ovarian compensation in unilaterally ovariectomized, immature mice injected with gonadotrophins?

The effect of unilateral ovariectomy on ovulation rates in immature mice was studied. Ovulations were induced by injecting PMSG and hCG and their number was determined by counting tubal oocytes. A 2--3-fold increase in number of ovulations per ovary was observed after unilateral ovariectomy, and daily injections of progesterone abolished this ovulatory compensation. No significant increase in serum concentrations of immunoreactive FSH and LH was observed at 4, 8, 32 and 51 h after unilateral ovariectomy. Progesterone treatment lowered FSH levels at all times, while LH was unaffected. In intact mice, ovarian sensitivity to PMSG and hCG was not substantially affected by progesterone. Ovulatory compensation in immature gonadotrophin-injected mice appears to arise through a negative feedback mechanism and transiently increased secretion of pituitary gonadotrophin rather than through a greater utilization of a fixed amount of gonadotrophin.


Polyamine inhibition of the conversion of human proacrosin to acrosin.

The conversion of human proacrosin to acrosin was inhibited by polyamines. The order of effectiveness was spermine greater than spermidine greater than cadaverine greater than putrescine greater than 1,3,-diaminopropane. These results are similar to those obtained for the conversion of boar proacrosin to acrosin. Unlike the effects on boar acrosin, however, polyamines did not affect the esterolytic activity of human acrosin but had a slight stimulatory effect on the proteolytic activity of human acrosin.


Chorionic gonadotrophin in the mouse from implantation to term.

Chorionic gonadotrophin (CG) in implantation sites from Days 5 to 12 and placentae from Days 13 to 19 of pregnancy in the mouse was determined by utilizing a cross-reaction with human CG in a radioimmunoassay. Significant amounts of CG could be detected throughout the period of gestation investigated. The amount of CG per implantation site increased steadily from Day 5 to a peak on Day 11. In the second part of pregnancy a second peak was observed with the highest amount of CG per placenta found on Day 16. No gonadotrophic activity could be detected in blastocysts flushed from the uteri on Day 5 of pregnancy or in uteri of non-pregnant mice.


Activity of ovarian delta 5-3 beta-hydroxysteroid dehydrogenase in the domestic fowl (Gallus domesticus) with respect to age.

The distribution of delta 5-3 beta-hydroxysteroid dehydrogenase was examined in the ovaries of hens aged 8--30 weeks. At all ages the interstitial cells (both thecal and stromal) gave a positive formazan reaction, but a positive reaction was not obtained in the granulosa cells of follicles less than 5 mm diameter in mature or immature birds. Since activity was restricted to follicles of larger size than this, it is concluded that steroidogenesis occurs in the granulosa cells for only the last 7--8 days of their life in the preovulatory follicle.


Effects of castration, 5 alpha-dihydrotestosterone and cyproterone acetate on enzyme activity in the mouse epididymis.

The influence of castration, androgen replacement therapy and cyproterone acetate on the activity of beta-glucuronidase, acid and alkaline phosphatases and glucose-6-phosphate dehydrogenase was studied in the caput, corpus and cauda epididymidis of the mouse. The results add further evidence that the epididymis is not uniform but has regional differences in activity. Thus beta-glucuronidase was found to be androgen-dependent only in the cauda epididymidis, whereas glucose-6-phosphate dehydrogenase was under androgenic control in the caput epididymidis. The response of alkaline and acid phosphatases to castration and to androgen replacement was different in different segments.


Studies on the contractile activity and ultrastructure of the boar testicular capsule.

The ultrastructure and the spontaneous and drug-induced contractility of the testicular capsule of 18 boars were investigated. Isometric recordings were obtained in vitro using strips of the tunica albuginea isolated from various regions of the testis. Maximal contractile activity was found in the strips of the posterior border of the testis, in which the histological studies (light and electron microscopy) showed abundant typical smooth muscle cells distributed in layers parallel to the testicular long axis. These cells were largely aggregated in the inner layer of the testicular capsule, which displayed contractile activity similar to that of the entire tunica albuginea. The outer layer of the tunica albuginea was almost totally devoid of smooth muscle fibres and showed little or no contractility. The spontaneous contractions were rhythmic and exhibited an amplitude of 20--70 mg and a frequency of 5--30 contractions/10 min. Norepinephrine, acetylcholine and oxytocin all produced an increase of the contractility of the tunica albuginea, consisting mainly in a rise of the tone.


Effect of cycloheximide on the ovine corpus luteum: the role of granules in the secretion of progesterone.

Cycloheximide (3 mg/h) was infused into the corpus luteum of the sheep via a side branch of the ovarian artery. The concentration of progesterone in the peripheral plasma and the luteal tissue decreased after the infusion. Ultrastructural studies showed that cycloheximide caused inhibition of the formation and secretion of densely stained granules in the luteal cells. The results provide further evidence that progesterone bound to protein is secreted by the luteal cell in the form of granules.


Effect of oestradiol-17 beta and progesterone on oviductal transport and early development of mouse embryos.

Transport of embryos through the oviduct, cleavage rate and transformation of morulae to blastocysts, were delayed in females ovariectomized on Day 2 of pregnancy. Oestradiol-17 beta in doses of 60 to 6000 pg/day for 3 days did not normalize the transport of embryos, but the transformation of morulae to blastocysts reached values near or equal to those of the controls, in spite of a lowered rate of cleavage. Progesterone at a dose of 100 micrograms/day, resulted in normal transport, rate of cleavage and rate of differentiation. Treatment with both hormones had synergistic effects on transport and the rate of cleavage and differentiation. These results give further support to the concept that ovarian hormones are the controlling factors for these processes in early pregnancy.


Granulocytes in the endometrium of post-partum women.

Endometrial samples of women at various stages of gonadal activity after parturition were examined for the presence and numbers of endometrial granulocytes. Although samples at all the stages contained significant numbers of the granulocytes (i.e. greater than 7/high-power field), the 100% values for late-proliferative and adaptation hyperplasia were significantly higher than the values for the resting (81.8%), early (82.4%) and mid- (87.9%) proliferative and secretory (83.3%) phases. We suggest that this correlates with the suggestion that the granulocytes constitute a receptor system for oestrogens.


Onset of puberty and duration of fertility in rats fed a restricted diet.

Chronic dietary restriction such that the body weight of CFY Sprague-Dawley female rats was 50% that of animals fed ad libitum resulted in enhanced longevity (LD 50 of 1090 days compared to 704 days). All the experimental females had reached puberty by 227 days and 80% were able to conceive and wean young at 510 days, an age beyond that at which the control rats had ceased to breed (450 days). Some (25%) of the experimental rats were able to breed at over 800 days of age.


Changes in ovine cervical mucus in response to oestrogen treatment.

After 10 days pretreatment with 10 mg progesterone daily, ovariectomized ewes were injected i.m. with 12.5, 25, 50 or 100 micrograms oestradiol benzoate (OB) and cervical mucus was collected 16, 24, 32, 40 and 48 h later (Exp. 1), or were injected with 12.5, 40 or 100 micrograms OB daily, and the mucus examined, for 9 days (Exp. 2). The Spinnbarkeit was affected by the dose of OB over 9 days, but at all doses it increased over the first 3 days of treatment (Exp. 2). The wet weight of the mucus, the amount and proportion of water, and therefore the degree of arborization, increased with the dose of OB but decreased after 3 days in Exp. 2. The amount of dry matter, protein or carbohydrate did not have any clear relationship to dose or duration of OB treatment.


Serum concentrations of oestradiol and progesterone during the normal oestrous cycle and early pregnancy in the lion (Panthera leo).

During a 6-month study period weekly serum samples demonstrated 9 oestradiol surges above 14 pg/ml (range 19-108 pg/ml) among 3 lionesses isolated from male lions. Intervals between peaks ranged from 3 to 8 weeks. Progesterone surges of more than 17 ng/ml (range 17-282 ng/ml) and lasting for 2-6 weeks were recorded after 7 of the oestradiol peaks. Sexual behaviour correlated well with the oestradiol peaks. Except for cornification following oestradiol peaks, there was no obvious vaginal cytology pattern at other times of the cycle. Pregnancy occurred after a 12-h contact with a male during behavioural oestrus. During gestation (108 days) oestradiol values remained low, while progesterone was elevated to 49 ng/ml within 12 h after mating, reaching a peak of 143 ng/ml at the 4th week, and remaining elevated during the next 2 months.


Effects of various lighting regimens and pinealectomy on semen production in Romney rams.

Sixteen Romney rams were utilized in a 2 x 2 factorial experiment designed to evaluate the effects on semen production of (i) contrasting lighting regimens, and (ii) pinealectomy or sham-operation. Reversal of the annual photoperiodic cycle advanced the seasonal peak of fructose levels in semen by 4 months and also reduced percentages of unstained and morphologically normal spermatozoa. Pinealectomy abolished this advancement of peak fructose production and reduced overall concentrations and motility of spermatozoa. Moreover, towards the end of the study pinealectomized rams had higher ejaculate volumes than did sham-operated rams. Testicular and accessory sex gland data obtained after the rams were killed showed a marked influence of the lighting regimen: high values from sham-operated rams in short daily photoperiods contrasted with depressed values from those in long daily photoperiods. Pinealectomized rams provided values midway between these extremes, a finding which suggested both anti- and pro-gonadotrophic roles for the pineal gland in rams.


Gonadotrophin-inhibiting activity in seminal plasma from intact and vasectomized bulls.

Bull seminal plasma administered to male rats at the time of castration inhibited the rise in the levels of FSH and LH otherwise seen in the serum 24 h later. That the gonadotrophin-inhibiting activity was also present in the seminal plasma from vasectomized bulls suggests that it was not of testicular origin. Although the substance with gonadotrophin-inhibiting activity was a protein, it may be chemically distinct from inhibin.


Evidence of the origin of the gelatinous masses in the oviducts of mares.

The gelatinous masses known to occur in the mare oviduct were examined by light and scanning electron microscopy. Many (44%) of the masses which occurred in 16 of the 24 oviducts studied were connected with the mucosa of the ampulla near the ampullary-isthmic junction. The masses consisted of lobules of fine fibres probably derived from the fibrous connective tissue of the lamina propria in the oviductal mucosa.


The location of eggs retained in the oviducts of mares.

The oviducts of 24 mares were examined to determine the site of retention of unfertilized eggs. The ampullary-isthmic junction regions of 42 of the 48 oviducts were serially sectioned and examined histologically. The remaining parts of the oviducts were flushed and the flushings searched microscopically. Of 45 eggs located, 40 were in the sectioned segments of 24 oviducts and only 5 were in the flushings. All but one of the sectioned segments contained prominent masses of material obstructing the lumen, but these were apparently not the direct cause of egg retention since eggs were found on both sides of them.


Short- and long-term effects of hypophysectomy and unilateral ovariectomy on ovarian follicular populations in sheep.

The effects of hypophysectomy and unilateral ovariectomy on the total number of follicles with greater than 3 layers of granulosa cells were determined at 4 and 70 days following treatment. The population of preantral follicles (less than 0.23 min diam.) was found to be under the control of gonadotrophins but such control was only evident on a long-term basis. At 70 days after unilateral ovariectomy there was a large increase in the number of preantral follicles but at 70 days after hypophysectomy there was a large decrease. The population of antral follicles (greater than 0.23 mm diam.) was under the immediate control of gonadotrophins. By 4 days after hypophysectomy all large antral follicles had become atretic and the number of antral follicles was further decreased at 70 days after treatment. At 70 days after unilateral ovariectomy there was an increase in the number of antral follicles. The follicular growth rates at 70 days following treatment were decreased in hypophysectomized ewes but increased in ewes after unilateral ovariectomy.


Selecting a mammalian species for the separation of X- and Y-chromosome-bearing spermatozoa.

All (524) male karyotypes in An Atlas of Mammalian Chromosomes (Hsu & Benirschke, 1967-1977) were visually estimated for the chromatin difference between the X- and Y-chromosome-bearing spermatozoa. After more exact measurement of axial chromatid length for 100 karotypes, 24 species were found in which the difference between X and Y chromosomes was greater than 6.2%. It is suggested that such species would be the best for attempts to separate the X- and Y-bearing spermatozoa.


Morphological characteristics of male germ cells of rats in contact with Sertoli cells in vitro.

Fragments of seminiferous epithelium were prepared from 3-week-old rats. Although the Sertoli cells formed a monolayer, germ cells (spermatogonia and early spermatocytes) remained in association with them and were of normal ultrastructural appearance. Germ cells became completely separated from Sertoli cells after 3 weeks of culture in a chemically defined medium. The contact areas between Sertoli and germ cells were characterized by desmosome-like junctions while those between germ cells appeared to be pentalaminar.


A cytogenetic study of the Caspian pony.

The group of Caspian ponies studied contained some animals with 65 chromosomes and others with 64 chromosomes. The morphology and G-banding pattern of the chromosomes resembled those of Equus caballus and E. przewalskii. The karyogram of animals with 65 chromosomes was identical to that of the cross between E. caballus and E. przewalskii. It is suggested that the Caspian pony is the product of natural hybridization between E. caballus and E. prezwalskii. Low reproductive effeciency of the Caspian pony is suggested as the cause of decline in the population of these animals.


Effect of the fetal placenta and of a rabbit pituitary extract on plasma progesterone in fetectomized rabbits.

When fetuses and placentas were removed on Day 18 in normal pregnant rabbits, plasma progesterone levels declined rapidly to non-pregnant values within 48 h. This decline was largely prevented if only fetectomy was performed, leaving the placentas in situ, but not when the fetal components of the placentas were also removed. These results suggested that ovarian progesterone production was dependent upon trophic influences emanating from the fetal portions of the placentas. Ovarian progesterone production was maintained by an extract of rabbit pituitaries for at least 72 h after removal of fetuses and placentas.


Fetal and placental weight relationships in the rat at days 13 and 17 of gestation.

Mean fetal and placental weights were, respectively, 0.018 and 0.051 g on Day 13 and 0.376 and 0.250 g on Day 17. Fetal and placental weights within litters were weakly correlated on Day 13 (r = 0.322) but not on Day 17. Litter size was negatively correlated with placental weight on Day 17 (r = -0.485) but not with fetal weight. Male fetuses were heavier than female fetuses on Day 17 but their placentas were not significantly different. Fetuses and placentas were lighter at the ovarian end of the uterine horn on both days examined, revealing an early influence of local environmental factors on their growth.


Cytogenetics and reproduction of sheep with multiple centric fusions (Robertsonian translocations).

The significance of centric fusions (Robertsonian translocations) in domestic animals, with special reference to sheep, is reviewed. The mating is described of a further 856 ewes with either a normal chromosome number 2n = 54 or carrying one or more of the three different translocations (centric fusions) t1, t2 and t3 in various heterozygous and homozygous arrangements. Rams which were used in the matings were homozygous for one of the translocation chromosomes (2n = 52), double heterozygotes (2n = 52), triple heterozygotes (2n = 51) or were carriers of 4 translocation chromosomes (2n = 50) and 5 translocation chromosomes (2n = 49). A remarkably even distribution of segregation products was recorded in the progeny of all combinations of translocation ewes x translocation rams in those groups in which sufficient animals were available for statistical analysis. Forty-eight chromosomally different groups of animals were mated. Further, the overall fertility of the translocation sheep, measured by conception rate to first service, lambing percentage and number of ewes which did not breed a lamb, was not significantly different from New Zealand national sheep breeding data. In some groups the poorer reproductive performance could be explained by the age structure of the flock and inbreeding depression, which probably affected the performance of some animals. Sheep with progressively decreasing chromosome numbers, due to centric fusion, 2n = 50, 2n = 49 and 2n = 48, are reported. The 2n = 48 category represents a triple homozygous ewe and a triple homozygous ram and is the first report of the viable evolution of such domestic animals. Less than 1% of phenotypically abnormal lambs were recorded in a total of 1995 progeny born over 10 years. It is now considered that there is little or no evidence to suggest that centric fusions in a variety of combinations affect the total productive fitness of domestic sheep. It is suggested that future research should be more actively directed to understanding their genetic significance.


Detection of induced death of embryos in sheep by the rosette inhibition test.

The rosette inhibition test has been used to monitor the decrease of an 'early pregnancy factor' in 2 groups of pregnant sheep (19-21 days) in which embryos were removed surgically or by induction of luteolysis with cloprostenol. The rosette inhibition titres of sera taken from sheep of each group declined from high (16-18) to low (8-10) levels within 48 h of treatment. Surgical removal of embryos caused little change in serum progesterone concentration whereas cloprostenol prompted a rapid decrease over the same period. Death of the embryo can therefore be detected by the rosette inhibition test within 48 h of occurrence, but not necessarily by the measurement of progesterone in blood within this period.


Within-subject variability of human semen in regard to sperm count, volume, total number of spermatozoa and length of abstinence.

The within-subject variability of the semen sperm count (n), volume (v) and the total number of spermatozoa (N) was studied on 220 ejaculates from 36 normal subjects after an abstinence of 7 days or less. For each of the three variables, the within-subject standard deviation, sigma, was practically proportional to the mean, mu; the common value of the coefficient of variation sigma/mu for all subjects was very high: 0.39 for n, 0.28 for v and 0.55 for N. The 95% confidence intervals based on a single ejaculate were asymmetrical and very large, the lower and upper limits being respectively 0.5 x n and 2.3 x n; 0.7 x v and 1.8 x v; 0.4 x N and 2.9 x N. The three semen characteristics for a given subject were highly correlated with length of abstinence: for an increase in abstinence of 1 day there were mean increments of 13 x 10(6)/ml for n, 0.4 ml for v, and 87 x 10(6) for N.


Detection of anti-Müllerian activity in boar rete testis fluid.

Boar rete testis fluid was tested for its capacity to induce Müllerian regression in 14.5-day-old rat Müllerian ducts. Weak activity was present in crude RTF, but after gel filtration 5-fold concentration, greater activity was detected in 1 our of 7 pools of the eluted fractions. The biologically active fraction (mol. wt 160 000-310 000) coincided with the elution of authentic labelled anti-Müllerian hormone, obtained from bovine fetal testes. These results indicate that a small amount of anti-Müllerian hormone is still synthesized in post-natal life.


Exteroceptive factors and pregnancy block in the Mongolian gerbil, Meriones unguiculatus.

A series of experiments based on 150 newly mated, uni- and multi-parous Mongolian gerbils provided no evidence for the existence of pregnancy blocking due to a strangle male effect. The reduced level of fertility observed was attributed to stressful factors at critical times in the pregnancy. Treatment with 10 i.u. PMSG on the day following mating interrupted pregnancy and the majority of females mated again within 4 days.


Increase of total protein synthesis during mouse oocyte growth.

Quantitative changes of mouse oocyte protein synthesis during oogenesis have been studied by determining the rate of leucine incorporation into total cell protein. The leucine intracellular poor was artificially expanded by exposing the isolated oocytes to different concentrations of radiolabelled leucine, and leucine incorporation was followed as a function of the time. Protein synthesis by mouse oocytes increases linearly with the increase of the cell volume, and such increase is constant throughout the entire period of oocyte growth.


Spontaneous electrical activity of the rat epididymis in vitro.

Smooth muscle electrical activity was recorded with suction electrodes from the partly or completely uncoiled epididymal duct of the rat in vitro. The electrical activity of the cauda epididymidis consisted of one or few spikes followed by a plateau of 1-2 sec. The frequency of electrical activity declined from the thicker-walled initial segment of the thin-walled initial segment, was increased to the level seen in the initial segment in the thicker, major portion of the caput epididymidis, declined in the corpus and fell steeply in the cauda epididymidis towards the vas deferens. Electrical activity spread over long distances in the distal cauda and epididymal vas. Elsewhere in the epididymis activity remained synchronous only for a short period in short segments.