Intoxication with beta-sympathicolytics.

Based on the review of available literature, this article states the possible clinical problems with beta-blocker intoxication. Some 26% of severe cases of intoxication will die. This fact stimulated the attempt, using animal experiments, to gain an insight into the pathophysiological profile of this intoxication. The results of these animal experiments led to the following conclusion: toxic doses of beta-blockers result in a dose-dependent decrease of myocardial contractility. This negative inotropic effect is not related to the antagonizing effects of the beta-blocker at the beta-adrenergic receptor level, nor to the additional properties of this group of drugs, but is influenced by a combination of other factors. These include (1) a direct negative inotropic effect on the myocardium, probably caused by a calcium dependent mechanism; (2) a decrease in serum calcium concentration, probably caused by a decreased parathormone production; (3) a centrally mediated hypotensive action. Toxic doses of beta-blockers do not only affect the myocardium and the haemodynamic system, they can also lead to respiratory arrest. This arrest is caused by the direct effect of these drugs on the central nervous system and can, in itself, be the cause of death. Such results lead to the following therapeutic advice: patients with severe beta-blocker intoxication must be admitted to an Intensive Care Unit, as early initiation of ventilation, as well as administration of beta-antagonist can be essential; the drop in serum calcium concentration must be corrected; drugs which can improve myocardial contractility, other than via the beta-adrenergic receptor, such as phosphodiesterase inhibitors and glucagon, should be administered.


Positive correlation between proopiomelanocortin and tyrosine hydroxylase mRNA levels in the mediobasohypothalamus of ovariectomized rats: response to estradiol replacement and withdrawal.

We have investigated putative dopaminergic regulation of opiomelanotropinergic activity in the arcuate/periarcuate mediobasohypothalamus (MBH) by assessing the changes in MBH tyrosine hydroxylase (TH; rate-limiting enzyme in catecholamine synthesis) and proopiomelanocortin (POMC; opiomelanotropin precursor) mRNA levels under conditions in which endogenous tuberinfundibular dopaminergic activity exhibits marked changes. Adult Sprague-Dawley rats were sacrificed at 09.00 and 15.00 h, and individual MBH POMC and TH cytoplasmic mRNA levels were simultaneously quantified by multiplex solution hybridization-RNase protection assay with protected fragments separated by polyacrylamide gel electrophoresis. In ovariectomized (OVX) rats treated for 3 days with low-dose estradiol (E2) implants (resulting in 18 +/- 4 pg E2/ml serum), the MBH levels of POMC and TH mRNAs were approximately 17 and 31% lower than those measured in OVX controls, respectively. In OVX rats implanted for 20 days with larger E2 implants (99 +/- 9 pg E2/ml serum), POMC and TH mRNA levels were approximately 29 and 41% lower than in OVX controls, respectively. Additional groups were exposed to the higher E2 dose for 20 days and then killed 10 or 20 days after removal of the E2 implant. In these rats, POMC mRNA levels rebounded to the same level seen in OVX controls, while TH mRNA levels even exceeded control values by 22-27%. TH and POMC mRNA levels did not change significantly between 09.00 and 15.00 h, except 10 days after removal of the E2 implants, when 09.00 h POMC mRNA levels were higher than the 15.00 h levels. MBH POMC and TH mRNA levels were positively correlated with each other within individual animals. This correlation is maintained when both POMC and TH mRNA levels are suppressed in response to both 3-day low-dose and 20-day high-dose E2 treatment. However, although rat MBH opiomelanotropinergic and tuberoinfundibular dopaminergic mRNA biosynthesis thus appear to be positively correlated, the coregulation or functional interactions of these two neuronal systems remain to be determined.


Dexmedetomidine, a potent and highly specific alpha 2 agonist, evokes cytosolic calcium surge in astrocytes but not in neurons.

Dexmedetomidine is an extremely potent alpha 2 adrenoceptor agonist which can reduce anaesthetic requirements by up to 90%. However, the precise cellular mechanism of action of this agent is not known. Primary cultures of murine neurons and astrocytes were grown to test the hypothesis that changes in free intracellular calcium may trigger cellular responses to this drug. In astrocyte cultures, experiments revealed a pronounced increase in cytosolic calcium concentration when 100 nM dexmedetomidine was administered. However, in cultured cerebellar granule cell neurons there was no calcium response observed with similar or even higher concentrations of the drug. Results suggest dexmedetomidine may exert its primary effect on the central nervous system via astrocytes.


Neuroendocrine responses to the serotonin2 agonist DOI are differentially modified by three 5-HT1A agonists.

Evidence suggests that activation of 5-HT1A receptors leads to inhibition of 5-HT2-mediated behavior. The purpose of this study was to investigate the interaction between 5-HT1A and 5-HT2 receptor-mediated hormone secretion. Rats were pretreated with the 5-HT1A agonists buspirone (0, 0.5, 2.0 mg/kg, i.p.), 8-OH-DPAT (0, 0.05, 0.2 mg/kg, s.c.) or ipsapirone (0, 1.0, 2.5 mg/kg, i.p.), 45 min before decapitation. The 5-HT2 agonist DOI was administered (0-10 mg/kg, i.p.) 15 min after injection of the 5-HT1A agonists. The three 5-HT1A agonists differentially altered the DOI-induced increase of concentrations of hormone in plasma. None of the three 5-HT1A agonists influenced the basal levels of renin, ACTH and prolactin but 8-OH-DPAT and buspirone increased the basal level of corticosterone in plasma. Also, 8-OH-DPAT increased the effects of DOI on the concentration of ACTH in plasma but ipsapirone and buspirone did not. None of the 5-HT1A agonists significantly affected DOI-induced increase of concentration of corticosterone in plasma. Buspirone and 8-OH-DPAT potentiated the effect of DOI on prolactin in plasma, but ipsapirone did not. Ipsapirone potentiated the effect of DOI on the concentration of renin in plasma but this effect was not observed in 8-OH-DPAT- and buspirone-pretreated rats. The results do not support the hypothesis for a functional interaction between 5-HT1A and 5-HT2 receptors, since the three 5-HT1A agonists did not have the same influence on the hormonal effects of DOI.


Effects of intracerebroventricularly administered mu-, delta- and kappa-opioid agonists on locomotor activity of the guinea pig and the pharmacology of the locomotor response to U50,488H.

The effects of intracerebroventricular administration of morphine, the selective mu-agonist DAMGO, the delta-agonist DPDPE, the kappa-preferring peptide dynorphin A(1-13) and the kappa-agonist U50,488H on locomotor behaviour in the guinea pig were investigated. Morphine (total dose = 0.01, 0.1, 1, 10, 200 nmol), DAMGO and DPDPE (total dose = 0.1, 1, 10, 100 nmol of each) produced piloerection and sedation, indicating that the responses of guinea pigs to mu- and delta-opioid agonists differed from those of rats and mice. In contrast, U50,488H (total dose = 10, 100 nmol) and dynorphin A(1-13) (total dose = 100 nmol) produced increased locomotor activity which was attenuated by pretreatment with naloxone and norbinaltorphimine, thus confirming the involvement of kappa-opioid receptors. Furthermore, pretreatment with spantide, baclofen, muscimol, bicuculline, MK-801, raclopride and atropine also inhibited the U50,488H-induced locomotor activity, suggesting the involvement of GABA, dopamine, excitatory amino acids, substance P and acetylcholine in this response.


Further studies of the role of opioid receptors in the nigra in the morphine withdrawal syndrome.

Bilateral injection of naloxone (3.0-30.0 nmol) into the substantia nigra of morphine-dependent rats produced a withdrawal syndrome consisting of wet-dog shakes, teeth chattering, irritability to touch, diarrhea and hypothermia. Intense wet-dog shakes and grooming were observed after intranigral injection of the mu selective antagonist D-Phe-Cys-Try-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP, 3.0-30.0 nmol) in morphine-dependent animals. Body temperature after 30.0 nmol CTOP was significantly increased. A significant positive correlation between body temperature and wet-dog shakes was observed in morphine-dependent animals that received CTOP. Intranigral injection of beta-funaltrexamine (beta-FNA, 10.0 nmol), an irreversible mu antagonist, produced no signs of withdrawal in morphine-dependent animals. However, intranigral injection of beta-FNA (1.0-3.0 nmol) suppressed the antinociceptive effect of the mu-selective agonist, D-Ala2,N-Me-Phe4,Gly5-ol-enkephalin (DAGO, 1.0 nmol). The withdrawal syndrome produced by CTOP (10.0 nmol) was not suppressed by the administration of U50,488H (10.0 nmol), a kappa agonist, suggesting that the absence of an effect of beta-FNA was not due to its kappa agonist activity. Neither the delta-selective antagonist, naltrindole (NTI, 10.0 nmol) nor the kappa-selective antagonist, nor-binaltorphimine (nor-BNI, 10.0 nmol) produced withdrawal. Only wet-dog shakes were observed when CTOP, NTI and nor-BNI (5 nmol each) were administered together into the nigra. These studies suggest an involvement of mu receptors in the nigra in the wet-dog shakes and thermoregulatory dysfunction that occur during withdrawal of morphine. However, the subtypes of opioid receptors in the nigra, that mediate the other signs of morphine withdrawal remain obscure.


Systemic administration of dynorphin A(1-13) markedly inhibits different behavioural responses induced by cocaine in the mouse.

The effects of systemic administration (i.p.) of dynorphin A(1-13) on the cocaine-induced behavioural alterations in the mouse were determined by using multi-dimensional behavioural analyses, based upon a capacitance system. A 1.0 mg/kg dose of cocaine did not influence behaviour, while increasing doses to 3-30 mg/kg produced a significant increment in the frequency of behaviour, such as linear locomotion, circling, rearing and grooming. Although a 1.0 mg/kg dose of dynorphin A(1-13) alone produced a significant decrease in grooming behaviour, larger doses (3.0 and 10.0 mg/kg) of the peptide failed to affect different behaviour. The cocaine (3.0 mg/kg)-induced increases in linear locomotion, circling and rearing behaviour were significantly inhibited by dynorphin A(1-13) (10.0 mg/kg). The inhibitory effects of dynorphin A(1-13) (10.0 mg/kg) were antagonized by the opioid antagonist Mr 2266 (5.6 mg/kg). It is thus possible that the systemic administration of dynorphin A(1-13) inhibits different behavioural responses induced by cocaine through the blood-brain barrier, although the instability of amino acid bonds or the relatively large molecular weight of dynorphin A(1-13), may result in the failure to demonstrate opioid activity by the peptide after systemic administration.


Interactions of endogenous opioid and excitatory amino acid inputs to the caudal ventrolateral medulla of the rat.

This study investigated the cardiovascular consequences of interactions between endogenous opioid and excitatory amino acid inputs to the caudal ventrolateral medulla of the anaesthetised rat. Drugs were injected bilaterally into the functionally identified depressor region of the caudal ventrolateral medulla. The opioid antagonist, naloxone (2.5-8.0 nmol/side) elicited a dose-dependent decrease in blood pressure and a bradycardia. The NMDA-receptor antagonist, 2-amino, 5-phosphonovaleric acid (2-APV; 1.25-500 pmol/side), dose-dependently increased blood pressure but had little effect on heart rate. After the maximum dose of naloxone, the pressor response to both 1.25 and 25 pmol/side of 2-APV was attenuated by 89 and 66%, respectively. By contrast, the pressor response, elicited by injection of the GABA agonist, muscimol (1 pmol/side), was not affected. After 2-APV (500 pmol/side), the depressor response to 2.5 nmol/side of naloxone was enhanced by 84%, although this effect was lost when a larger dose of naloxone (5 nmol/side) was used. 2-Amino,5-phosphonovaleric acid also potentiated the depressor response to a submaximal dose of the GABA antagonist, bicuculline (2 pmol/side). The results suggest firstly that, in the caudal ventrolateral medulla, excitatory amino acid inputs are functionally less important when tonic opioid effects are blocked. This interaction appears to be pharmacologically specific. Secondly, tonic inhibitory inputs, whether due to opioids or to GABA, are functionally more effective after excitatory amino acid inputs are antagonized.


Repeated administration of MDMA causes transient down-regulation of serotonin 5-HT2 receptors.

The present study examined short- and long-term effects of MDMA (3,4-methylene-dioxymethamphetamine) on serotonin (5-HT2 and 5-HT1c) receptors in the brain of the rat. N1-Methyl-2-[125I]lysergic acid diethylamide ([125I]MIL) was used to label these receptors in vitro and in vivo. The usefulness of [125I]MIL for in vivo detection of changes in 5-HT2 receptors was confirmed in preliminary experiments in which rats were treated chronically with mianserin (5 mg/kg, once daily for 10 days). Decreases in specific in vivo binding of [125I]MIL, after treatment with mianserin were found to be of the same magnitude as those determined by others, using in vitro methods. The MDMA (8 doses; 5-20 mg/kg each) was administered to rats over a period of 4 days. At various times after administration of the last dose of MDMA, the binding of [125I]MIL was measured. Acutely, treatment with MDMA (20 mg/kg) reduced specific in vivo binding of [125I]MIL in all regions of brain studied. For example, in the frontal cortex, specific binding of [125I]MIL was decreased by 80% at 6 hr and by 62% at 24 hr, after cessation of treatment with MDMA. Twenty-one days after administration of MDMA however, the number of binding sites for [125I]MIL was back to control levels. Reductions in in vivo binding of [125I]MIL in frontal cortex were dependent on the dose of MDMA injected and were associated with decreases in the number of binding sites for [125I]MIL (Bmax values) in tissue homogenates of the same area. Autoradiographic studies of MDMA-treated rats confirmed the decreased density of 5-HT2 receptors and also suggested that the 5-HT1c receptor of the choroid plexus was not affected. These results indicate that repeated administration of MDMA caused transient down-regulation of 5-HT2 receptors in the brain of the rat. Further, they demonstrated that [125I]MIL is a suitable radioligand for labeling 5-HT2 receptors, both in vitro and in vivo. Once labeled with an appropriate radionuclide for SPECT (single photon emission computed tomography) or PET (positron emission tomography), MIL should prove useful for monitoring changes in the density of serotonin receptors in the living mammalian brain.


The effects of electroconvulsive shock or imipramine on subtypes of alpha 1-adrenoceptors in the frontal cortex of the rat.

The effects of repeated treatment (14 days) with electroconvulsive shock (ECS) or imipramine on binding sites on alpha 1-adrenoceptors in the rat were studied. The binding of [3H]prazosin studied with WB4101 and phentolamine, as binding inhibitors, showed the existence of two subtypes of alpha 1-adrenoceptor (alpha 1A and alpha 1B). Proportions of the alpha 1A and alpha 1B binding sites were about 3:7 in the frontal cortex and 9:1 in the hippocampus. Pretreatment of the membranes with chlorethylclonidine (CEC) almost abolished the alpha 1B binding sites. Inhibition of the binding of [3H]prazosin studied with antidepressants (imipramine, desipramine, maprotiline and mianserin) showed that these drugs bound to alpha 1-adrenoceptors with low affinity, in an apparent monophasic manner. The characteristics of the alpha 1A and alpha 1B binding sites were studied by the binding assay with [3H]prazosin, in the presence of a small concentration (2 nM) of WB4101 to mask the alpha 1A binding sites, as well as the assay without WB4101, for the total alpha 1-adrenoceptor (alpha 1A and alpha 1B) binding. Repeated treatment with electroconvulsive shock increased but that with imipramine decreased, the density of the alpha 1B binding sites in the frontal cortex, without change of the affinity. Neither treatment affected the alpha 1A binding sites in the frontal cortex. The alpha 1-adrenoceptors (alpha 1A and alpha 1B) in the hippocampus were not affected at all by these repeated treatments. The electroconvulsive shock-induced increase in the alpha 1B binding sites in the frontal cortex of the rat could contribute to differences in clinical effects between electroconvulsive shock and antidepressant drugs.


Lack of involvement of haloperidol-sensitive sigma binding sites in modulation of dopamine neuronal activity and induction of dystonias by antipsychotic drugs.

The present studies evaluated previous suggestions that haloperidol-sensitive sigma binding sites are involved in the modulation of dopamine (DA) neuronal activity and in the induction of the dystonic effects of antipsychotic drugs. These issues were addressed by evaluating the effects of compounds that have differing affinities for sigma binding sites, on the firing activity of DA neurons in the substantia nigra in chloral hydrate-anesthetized rats and on the ability to induce extrapyramidal motor dysfunction in squirrel monkeys sensitized to the dystonic effects of haloperidol. The agents studied included haloperidol, DTG (1,3-di-o-tolylguanidine), (+)-pentazocine, (+)-SKF 10,047, BMY 14802, 8-OH-DPAT and sulpiride. There was no relationship between affinity for sigma binding sites and the ability to either alter DA neuronal activity or to induce extrapyramidal motor dysfunction.


Differential modulation of Purkinje cell activity by enkephalin and corticotropin releasing factor.

Several peptides have been localized within afferents to the opossum's cerebellum, including cholecystokinin (15), enkephalin (16, 17) and corticotropin releasing factor (7, 9). Each of these peptides has a heterogeneous laminar and lobular distribution. Two peptide, enkephalin (ENK) and corticotropin releasing factor (CRF) are present in specific populations of climbing fibers and mossy fibers, which have an overlapping distribution in several areas of the cerebellum, in particular the lateral aspect of vermal lobules VII and VIII. Within this location ENK and CRF are co-localized in individual climbing fibers and mossy fibers (7). In the present study, the physiological effects of these peptides on Purkinje cell activity were analyzed. The data indicate that ENK and CRF have opposite effects on Purkinje cell activity. ENK suppresses spontaneous activity as well as that induced by application of glutamate and aspartate, as described previously (5). In contrast, CRF enhances both spontaneous and amino acid-induced unit activity. Further, when applied simultaneously, CRF blocks the suppressive effect induced by ENK. Previous studies have shown that climbing fibers, as well as the mossy fiber-parallel fiber pathway, are excitatory to Purkinje cells (11). However, immunohistochemical data have shown that these afferents are heterogeneous with respect to their chemical content (7-9, 15-17, 25). As found in the current and previous studies (3, 5) peptides in climbing and mossy fibers modulate the responsiveness of Purkinje cells to primary excitatory neurotransmitters in selected areas of the cerebellar cortex. However, the firing rate of individual Purkinje cells is differentially altered depending on which neurochemical messenger(s) are released.(ABSTRACT TRUNCATED AT 250 WORDS)


Contrast-enhanced magnetic resonance imaging of sub- and epidural empyemas.

Contrast-enhanced magnetic resonance images (MRI) of three patients with subdural (SDE) and two with epidural empyemas (EDE) were reviewed. In each case, the capsule of the lesion demonstrated enhancement, and distinction between capsule and contents was obvious on contrast-enhanced images. In SDE, contrast-enhanced images clearly depicted thickening of the neighbouring dura mater and a co-existent brain abscess. In EDE, part of the displaced dura mater did not enhance, which facilitated differentiation from SDE. Contrast-enhanced MRI was thus of value in diagnosis.


Analysis of synaptic events in the mouse accessory olfactory bulb with current source-density techniques.

The accessory olfactory bulb of the mouse was studied by current source-density analysis of field potentials to determine the laminar and temporal distribution of synaptic currents evoked by electrical stimulation of the vomeronasal organ. The one-dimensional current source-density analysis revealed two major spatially and temporally distinct inward membrane currents (sinks): one in the glomerular layer and the other in the external plexiform layer. The glomerular layer sink preceded the external plexiform layer sink by a mean of 5.5 ms. Local infusions of the broad-spectrum excitatory amino acid antagonist, kynurenate, into the accessory olfactory bulb blocked the external plexiform layer sink without an obvious effect on the glomerular layer sink. The selective non-N-methyl-D-aspartate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione produced a dose-dependent blockade of the external plexiform layer sink, whereas the selective N-methyl-D-aspartate receptor antagonist D-2-amino-5-phosphonovalerate was without effect. These results, taken together with the cytoarchitecture of the accessory olfactory bulb, suggest that the glomerular layer sink results mainly from synaptic excitation evoked in the glomerular dendritic branches of mitral cells by the vomeronasal afferent fibres and the external plexiform layer sink mainly from non-N-methyl-D-aspartate receptor-mediated synaptic excitation in the peripheral processes of granule cells via the mitral to granule cell dendrodendritic synapse.


D1 and D2 dopamine receptors differentially regulate c-fos expression in striatonigral and striatopallidal neurons.

The expression of Fos, the product of the proto-oncogene c-fos, is thought to be a marker of neuronal activity. D1, but not D2, dopamine receptor agonists have previously been shown to increase Fos immunoreactivity in striatonigral neurons ipsilateral to a 6-hydroxydopamine lesion of the nigrostriatal pathway. In the present study, it was demonstrated that the D1 receptor agonist SKF 38393 rarely increased Fos in striatopallidal neurons of the 6-hydroxydopamine denervated striatum. Conversely, in the intact striatum, the D2 receptor antagonist haloperidol enhanced Fos expression predominantly in striatopallidal neurons labelled retrogradely from the globus pallidus or with an oligonucleotide probe complementary to mRNA encoding enkephalin. These results are consistent with studies suggesting that D1 receptors are located predominantly on striatonigral neurons and that D2 receptors reside principally on enkephalin-containing striatopallidal neurons. They also provide a neuroanatomical basis for neurochemical and neurophysiological observations indicating that dopamine facilitates the activity of striatonigral neurons but inhibits striatopallidal neurons. In another experiment the selective D2 receptor agonist quinpirole was found to increase Fos immunoreactivity in the globus pallidus ipsilateral to a 6-hydroxydopamine lesion. It is proposed that this may have been due to a D2 receptor-mediated inhibition of enkephalin and GABA release from striatopallidal terminals that in turn disinhibited the pallidal neurons. In a final series of experiments, brain microdialysis was used to determine the location of dopamine receptors regulating striatal Fos expression. Local application of the selective D1 receptor agonist CY 208-243 in the 6-hydroxydopamine-denervated striatum, or of haloperidol in the intact striatum via the dialysis probe increased Fos immunoreactivity in the immediate vicinity of the probe. Hence, the inductive effects of these systematically administered compounds on Fos expression in the striatum are mediated at least partly by local dopamine receptors in the striatum. Taken together, these results suggest that the differential regulation of striatonigral and striatopallidal activity by dopamine is mediated by the largely separate location of D1 and D2 receptors on these outputs.


Acute and repeated administration of fluphenazine-N-mustard alters levels of tyrosine hydroxylase mRNA in subsets of mesencephalic dopaminergic neurons.

Changes in striatal dopamine turnover and levels of tyrosine hydroxylase messenger RNA were examined in mice injected with D2 selective doses of fluphenazine-N-mustard, an irreversible blocker of dopaminergic receptors. The animals were killed at different times after acute and repeated injections of the drug and dopamine turnover was assessed by measuring dopamine and its metabolite, dihydroxyphenylalanine, in the striatum. Tyrosine hydroxylase mRNA was measured at the single-cell level in neurons of the substantia nigra pars compacta and the ventral tegmental area with quantitative in situ hybridization histochemistry. Acute treatment with fluphenazine-N-mustard induced an increase in both striatal dopamine turnover and the level of tyrosine hydroxylase mRNA in the substantia nigra but not the ventral tegmental area. After two days of repeated drug injections (twice daily), tyrosine hydroxylase mRNA was decreased in the substantia nigra despite the persistence of an elevated dopamine turnover in the striatum. The decrease in mRNA was still observed after four days of repeated treatment while, at that time, turnover values were not different from control. No changes were observed in the ventral tegmental area. The initial increase in tyrosine hydroxylase mRNA in substantia nigra pars compacta suggests that activation of nigrostriatal neurons triggers a very rapid increase in genomic expression of the enzyme. The following decrease in mRNA levels precedes desensitization to the effects of the drug on dopamine turnover, further illustrating a lack of correspondence between increased neurotransmission and levels of tyrosine hydroxylase mRNA in catecholaminergic neurons of the central nervous system.


Role of dopamine receptors in the regulation of aggression in mice; relationship to genotype.

The interline differences in the manifestation of aggression evoked by stimulation was studied in mice of eight inbred lines, and the role of different types of dopamine (DA) receptors in its manifestation was investigated. Aggression was assessed in a test involving the effect of a weak electrical stimulation through the floor of the cage. A significant relationship to the animals' genotype was demonstrated, and low-aggression (C3h/He, DD, BALB/c, and AKR) and high-aggression (CBA, DBA/2, and CC57Br) lines could be distinguished on the basis of the level of aggressivity. The mixed agonist of DA receptors, apomorphine, in a one-time administration activated aggressivity in the low-aggression mice. The selective stimulation of D2-receptors with bromocriptine substantially increased the evoked aggressivity in the low-aggression mice; the blockade of D2-receptors by sulpiride decreased or prevented the manifestation of aggressivity in the high-aggression lines. At the same time, the selective D1-agonist SKF 38393 and the selective D1-antagonist SCH 23390 did not exert a substantial influence on evoked aggressivity. Evidently the D2-receptors play a key role in the control of aggression evoked by stimulation, which constitutes a model of affective aggression.


A neuroleptic-like effect of ceronapril on latent inhibition.

Three experiments that used a latent inhibition procedure to investigate the effects of ceronapril on attentional processes in the rat are reported. Latent inhibition is a behavioural paradigm in which prior exposure to a stimulus with no significant consequences retards subsequent conditioning to that stimulus when it is paired with reinforcement. Latent inhibition reflects a process of learning to ignore, or tune out, irrelevant stimuli, and has been suggested as an animal model of the attentional processes disrupted in the acute phase of schizophrenia. In animals, latent inhibition is disrupted by the administration of low doses of amphetamine and enhanced by the administration of neuroleptics. Ceronapril is an angiotensin converting enzyme inhibitor that has been shown to retard the breakdown of central cholecystokinin. It has been proposed that elevation of cholecystokinin levels in the brain may possess neuroleptic-like properties. We assessed this possibility by determining the effects of ceronapril on latent inhibition using a conditioned emotional response procedure, consisting of three stages: pre-exposure, in which the to-be-conditioned stimulus, a tone, was repeatedly presented without reinforcement; conditioning, in which the pre-exposed stimulus was paired with shock; and test, where latent inhibition was indexed by animals' suppression of licking during tone presentation. In Experiment 1, 20 tone pre-exposures were given, and conditioning consisted of five tone-shock pairings; we assessed the effects of 0.005 mg/kg, 0.05 mg/kg and 0.5 mg/kg ceronapril, compared with vehicle injections. In Experiment 2, five tone pre-exposures were given, and conditioning consisted of two tone-shock pairings: we assessed the effects of 0.05 mg/kg ceronapril, compared with vehicle injections.(ABSTRACT TRUNCATED AT 250 WORDS)


Dissociated high-purity dopaminergic neuron cultures from the substantia nigra and the ventral tegmental area of the postnatal rat.

We have developed dissociated primary neuronal cultures obtained from the substantia nigra and from the ventral tegmental area of postnatal rats (two to three days old). After making brain slices, the regions of the substantia nigra and the ventral tegmental area were separately dissected. The removed fragments of brain tissue were dissociated and cultured on a glial feeder layer. Double immunocytochemical labeling for tyrosine hydroxylase and GABA on cultures grown for two to three weeks showed the presence of 42% dopaminergic and 39% GABAergic neurons in substantia nigra cultures, whereas in ventral tegmental area cultures there were 65% dopaminergic and 21% GABAergic neurons. The dopaminergic neurons were characterized by thick and straight primary processes dividing into several branches. Varicosities were found mainly on distal parts of the processes. In contrast, GABAergic neurons possessed highly branched thick and thin primary processes with intensive arborization and numerous varicosities. Co-existence of dopamine and cholecystokinin was found in about 70% of dopaminergic neurons from the substantia nigra and in about 35% of dopaminergic neurons from the ventral tegmental area. Physiological properties of these cultured dopaminergic neurons were investigated with the whole-cell version of the patch-clamp method. After each physiological experiment, immunocytochemical labeling confirmed that the cell was dopaminergic. Properties of single action potentials, with an action potential height of 92 mV and duration of 1.6 ms, were similar to those reported for dopaminergic neurons in brain slices. The neurons showed a high resting potential, and no spontaneous firing of action potentials. Constant current depolarizations elicited trains of action potentials. In the majority of cells, the train stopped firing within a few seconds, while in some cells it lasted indefinitely. When the cell was hyperpolarized, the voltage response started to decline slowly (sag), indicating the presence of hyperpolarization-activated currents (time-dependent inward rectification). These results show that by using our culture method it is possible to obtain separate dissociated cultures of the substantia nigra and the ventral tegmental area from newborn rats. Because they are rich in functional dopaminergic neurons, these cultures will be a useful tool for studying various properties of dopaminergic neurons.


Pentylenetetrazol kindling and factors of glutamate transmitter metabolism in rat hippocampus.

Male Wistar rats administered repetitively with pentylenetetrazol developed a dose-dependent enhancement of seizure behaviour referred to as pentylenetetrazol kindling. After a daily dose of 40 mg pentylenetetrazol/kg or physiological saline (control rats) injected intraperitoneally for a period of two weeks, hippocampal tissue was studied autoradiographically for high-affinity uptake of [3H]glutamate and, by activity staining, for aspartate aminotransferase and glutamate dehydrogenase. Most prominent changes were found in neuropil areas known to be endowed with glutamatergic structures. The uptake capacity of glutamate decreased by 48% (maximum rate), whilst activities of aspartate aminotransferase and glutamate dehydrogenase elevated to 140 and 130%, respectively. Cytochrome c oxidase activity was found to be unaffected. The findings indicate an important role of factors of the glutamate metabolism in the kindling process with respect to the production, utilization, and availability of transmitter glutamate.


Inhibition of nigral dopamine neurons by systemic and local apomorphine: possible contribution of dendritic autoreceptors.

Peripheral administration of low doses of dopamine agonist apomorphine induces a strong and short-latency inhibition of dopamine neurons in the substantia nigra, presumably via the activation of somatodendritic autoreceptors. We studied the site of action of apomorphine in anesthetized rats using volume-controlled pressure microejection combined with single unit recordings. Microapplication of apomorphine in the immediate vicinity of nigral dopamine neurons did not mimic the effect of intravenous administration of apomorphine (50 micrograms/kg), regardless of the concentration or volume used (10(-10)-10(-2) M, 10-100 nl). In contrast, the inhibition produced by systemic apomorphine was mimicked by drug application at a site 300 microns lateral and 600 microns ventral from the recording site in the zona reticulata of the substantia nigra, a region rich in dendrites of dopamine neurons. The inhibition induced by such a distant application of apomorphine could be reversed by systemic injection of D2, but not D1, receptor antagonists. Non-dopaminergic substances such as GABA, bicuculline or lidocaine were more effective when ejected close to rather than distant from the recording site, in a manner opposite to that of apomorphine. Similar to apomorphine, dopamine and D2 receptor agonists were more potent when intranigral applications were made at sites distant from, rather than close to, the recorded dopamine cells. Ejection of D2 antagonists in the substantia nigra zona reticulata attenuated the inhibitory effect of subsequent systemic apomorphine. Our results, together with other previous studies on the location of D2 receptors on dopamine neurons, suggest that peripheral administration of low doses of apomorphine inhibits nigral dopamine neurons by acting at D2 receptors located on the dendrites of these neurons.


Excitatory synaptic potentials in neurons of the deep nuclei in olivo-cerebellar slice cultures.

Excitatory postsynaptic potentials evoked in neurons of the deep cerebellar nuclei, either by electrical stimulation within the nuclei in cerebellar slice cultures or by electrical stimulation of olivary explants in olivo-cerebellar co-cultures, were investigated in the rat by means of intracellular recordings. In neurons of the deep cerebellar nuclei, stimulation of the nuclear tissue, as well as stimulation of the olivary tissue, induced a fast rising excitatory postsynaptic potential, followed by an inhibitory postsynaptic potential and a long-lasting excitation. The fast rising excitatory postsynaptic potential and the following inhibitory postsynaptic potential were blocked by 6-cyano-7-nitroquinoxaline-2,3-dione. The remaining depolarization was abolished by D-(-)-2-amino-5-phosphonovalerate, suggesting that this potential was mediated by N-methyl-D-aspartate receptors. With only D-(-)-2-amino-5-phosphonovalerate added to the bath, the slow excitation was depressed, whereas the fast excitatory and inhibitory postsynaptic potentials were not affected. In the presence of bicuculline, the 6-cyano-7-nitroquinoxaline-2,3-dione- and the D-(-)-2-amino-5-phosphonovalerate-sensitive excitatory postsynaptic potentials elicited by stimulation of the olivary tissue had the same latency, and were both graded with stimulation strength. The time-to-peak and the duration of the D-(-)-2-amino-5-phosphonovalerate-sensitive excitatory postsynaptic potentials were considerably longer than those of the 6-cyano-7-nitroquinoxaline-2,3-dione-sensitive excitatory postsynaptic potentials.(ABSTRACT TRUNCATED AT 250 WORDS)


Cocaine induced synchronous oscillations in central noradrenergic neurons in vitro.

Through inhibition of reuptake, cocaine increases monoaminergic tone in the central nervous system. The activities of the neurons within the locus coeruleus play a pivotal role in central noradrenergic transmission and regulate overall levels of arousal and attention. We have found that cocaine in low concentrations (0.3-1.0 microM) induced slow oscillations (0.8 Hz) in membrane potential (2-6 mV). These oscillations were synchronized in neurons throughout the nucleus and were blocked by alpha 2-adrenergic receptor antagonists. The synchrony of these events was thought to arise from within the nucleus, through a combination of spontaneous activity (intrinsic properties) and noradrenergic mediated inhibitory postsynaptic potentials augmented by cocaine. The synchronous firing of noradrenergic neurons may facilitate transmitter release in the widespread projection areas and thus be important for the action of cocaine to increase levels of arousal.


Localization of oestrogen receptors in preoptic neurons containing neurotensin but not tyrosine hydroxylase, cholecystokinin or luteinizing hormone-releasing hormone in the male and female rat.

The neurochemical identity of preoptic neurons containing oestrogen receptors was investigated in the male and female rat using a sequential double-staining immunocytochemistry procedure. Single-immunostaining revealed large populations of cells with nuclear immunoreactivity to the oestrogen receptor in the medial preoptic area of the male and female rat. Optimal double-staining of sections for the oestrogen receptor and one of several neuropeptides or tyrosine hydroxylase, was achieved with short-term (two- to four-day) gonadectomized rats treated with colchicine where necessary. Neurotensin-immunoreactive cells were distributed in a sexually dimorphic manner in the region of the anteroventral preoptic nucleus and exhibited oestrogen receptor immunoreactivity in both sexes. Double-labelled cells in this area of the female rat comprised 50% and 11% of the total neurotensin- and oestrogen receptor-containing cell populations, respectively, compared with 25% and 4% in the male (P less than 0.01). The numbers of neurotensin-immunoreactive cells in the region of the medial preoptic nucleus were similar in male and female rats with double-labelled cells making up 20-38% and 3-5% of the total numbers of cells containing neurotensin and oestrogen receptors, respectively, in both sexes. Neurons immunoreactive for tyrosine hydroxylase were distributed in a gender-specific manner within the anterior periventricular area but were not immunoreactive for the oestrogen receptor in either sex. Following colchicine treatment, cholecystokinin-immunoreactive cells were identified predominantly within periventricular regions of the preoptic area and similarly, did not possess immunoreactivity to the oestrogen receptor in either the male or the female rat. Neurons containing luteinizing hormone-releasing hormone were found immediately lateral to the cell populations containing oestrogen receptors and immunoreactivity to the oestrogen receptor was not identified within any neurons containing luteinizing hormone-releasing hormone in either the male or female rat. The absence of oestrogen receptor immunoreactivity in neurons containing tyrosine hydroxylase, cholecystokinin or luteinizing hormone-releasing hormone suggests that gonadal steroids acting through this receptor do not influence these cells directly in either sex. In particular, it appears that gender-specific patterns of luteinizing hormone secretion cannot be attributed to sex differences in oestrogen receptor localization within luteinizing hormone-releasing hormone neurons. These experiments also show that the sexually dimorphic neurotensin neurons in the preoptic area possess oestrogen receptors and that female rats have larger number of neurons co-localizing neurotensin and oestrogen receptors. As such, these neurons may be involved in mediating sex-specific actions of the gonadal steroids in the preoptic area.


Pressure reversed extracellular striatal dopamine decrease produced by D1 receptor agonist SKF 38393, and D2 receptor agonist LY 171555, but failed to change the effect of the activation of both D1 and D2 receptors.

When human divers or experimental animals are exposed to high pressure, they develop the high-pressure neurological syndrome which is characterized by electroencephalographic changes, and behavioral disturbances. Recently, neurochemical disorders such as a pressure-induced increase in dopamine release have been demonstrated. In the present study, pharmacological experiments, using dopamine receptor agonists such as D1 receptor agonist SKF 38393, D2 receptor agonist LY 171555, and D1/D2 receptor agonist apomorphine, were performed to investigate dopamine receptor function at the neurochemical level. Only apomorphine and mixed SKF 38393 + LY 171555 prevented the pressure-induced increase in dopamine release while SKF 38393 or LY 171555 administered alone failed to do so. The results suggest that the D1-D2 link would be reduced under high pressure because of an abnormal function of D1 receptors which would allow high-affinity D2 states for dopamine. If so, such a preponderance of high-affinity states in D2 postsynaptic receptors could be associated with hyperbaric hyperlocomotor activity. Elsewhere, results also suggested that the pressure-induced disorders in dopamine receptor function could be involved in the pressure-induced elevation in dopamine release.


Neonatal hypoxic-ischemic or excitotoxic striatal injury results in a decreased adult number of substantia nigra neurons.

It has been shown that morphologic and biochemical presynaptic markers of dopaminergic terminals are preserved in a unilateral experimental model of neonatal hypoxic-ischemic injury to the striatum. As the substantia nigra is spared direct injury in this model, we anticipated that the number of tyrosine hydroxylase-positive dopaminergic neurons projecting to the striatum would also be normal. We have found, however, that following unilateral neonatal striatal injury the number of ipsilateral tyrosine hydroxylase-positive neurons is decreased, as is the mean area of the substantia nigra pars compacta. The decrease in neurons is correlated with the decrease in striatal size (r = 0.7, P = 0.01). Neuron loss is most pronounced in the substantia nigra pars reticulata, where it is 50%. Calbindin-positive neurons in the dorsal tier of the substantia nigra pars compacta appear to be preserved. We also examined effects on the nigra following a neonatal excitotoxic striatal lesion made with quinolinic acid. We observed a decrease in the number of substantia nigra tyrosine hydroxylase-positive neurons in the absence of direct nigral injury, and the decrease was closely correlated with reductions in striatal area (r = 0.91, p < 0.01). While there are a number of possible explanations for these observations, one major possibility is that there has been a reduction in tyrosine hydroxylase-positive neurons due to a diminution in developmental target-derived trophic support from the striatum. If striatum-derived trophic support plays a role in the developmental regulation of substantia nigra neuron number, then abnormalities in this supportive relationship may play a role in the loss of these neurons in some animal models of developmental nigral degeneration, and some forms of human parkinsonism.


Distributions of neuropeptide Y, vasoactive intestinal peptide and somatostatin in populations of postganglionic neurons innervating the rat kidney, spleen and intestine.

Some peripheral peptidergic nerves selectively innervate different types of tissue in abdominal organs. Neuropeptide Y- and vasoactive intestinal peptide-immunoreactive nerve terminals have been identified in the kidney, spleen and intestine and these peptides may have important physiological actions. Somatostatin has been found in sympathetic ganglia, and nerve terminals containing this peptide have been identified in the intestine. We have used fluorescent retrograde tracers to identify renal, splenic and mesenteric postganglionic neurons in rat sympathetic ganglia and then used immunocytochemistry to determine the proportions of these three identified groups of neurons displaying immunoreactivity for neuropeptide Y, vasoactive intestinal peptide and somatostatin. Most renal, splenic and mesenteric neurons were immunoreactive for neuropeptide Y and less than 1% of cells innervating these organs were immunoreactive for vasoactive intestinal peptide. Somatostatin immunoreactivity was present only in a small percentage of mesenteric neurons and not in renal or splenic neurons. The present study demonstrates that (i) the rat kidney, spleen and intestine do not differ in the proportion of innervation by neuropeptide Y-immunoreactive neurons, (ii) the solar plexus, splanchnic ganglion and chain ganglia (T12 and T13) provide very little vasoactive intestinal peptide-immunoreactive inputs to these organs, and (iii) somatostatin-immunoreactive neurons innervate the intestine but not the kidney or spleen.


Functional heterogeneity of the matrix compartment in the cat caudate nucleus as demonstrated by the cholinergic presynaptic regulation of dopamine release.

Previously, using a new in vitro microsuperfusion procedure, we have demonstrated marked differences in the cholinergic presynaptic regulation of the release of [3H]dopamine continuously synthesized from [3H]tyrosine in two close striosomal- and matrix-enriched areas of the cat caudate nucleus. A tetrodotoxin-resistant stimulatory effect of acetylcholine mediated by muscarinic receptors was observed in both compartments. However, in addition, two opposing types of tetrodotoxin-sensitive acetylcholine-evoked regulation of [3H]dopamine release were only seen in the matrix: one facilitatory, involving nicotinic receptors located on as yet unidentified neurons, and the other inhibitory, mediated by muscarinic receptors located on dynorphin-containing neurons. In the present study, using the same approach, a functional heterogeneity was demonstrated in the matrix. Indeed, in various conditions the effects of acetylcholine (50 microM) on the release of [3H]dopamine were different in a matrix-enriched area (matrix 2) distinct from that previously investigated (matrix 1); these areas being characterized by the presence or absence of islands of striatonigral cells, respectively. As in matrix 1, acetylcholine induced a short-lasting stimulation of [3H]dopamine release in matrix 2 but, in contrast to that observed in matrix 1, the acetylcholine-evoked response in matrix 2 was not modified in the presence of tetrodotoxin (1 microM). Experiments made in the presence of the tetrodotoxin and atropine (1 microM) indicated that both muscarinic and nicotinic receptors are located on dopaminergic nerve terminals in matrix 2 while muscarinic receptors are only present in matrix 1. In the absence of tetrodotoxin, the short-lasting stimulation of [3H]dopamine release was transformed into a long-lasting response in the presence of pempidine (50 microM), in matrix 2 but not in matrix 1 while prolonged responses were seen in both matrix areas in the presence of atropine. Finally, the acetylcholine short stimulatory effect on [3H]dopamine release was transformed into a long stimulatory response in the presence of bicuculline (50 microM) but not naloxone (1 microM) in matrix 2 while the reverse was observed in matrix 1. By providing further evidence for a functional heterogeneity of the matrix, our results suggest that depending on the matrix area investigated, dynorphin- or GABA-containing neurons are involved in the indirect cholinergic inhibitory control of dopamine release.


[The use of somatostatin in the therapy of acute pancreatitis].

The authors report their experience in the use of somatostatin in severe acute pancreatitis. From 1985 to 1990, 169 patients with severe acute pancreatitis have been observed in the Surgery Division of "S. Andrea" Hospital in Vercelli. After the introduction, the evaluation of methods employed and results obtained, the authors conclude that somatostatin can give a good response in this kind of patient without side effects or complications.


[The efficacy of the omeprazole-levosulpiride combination in the therapy of distal reflux esophagitis].

The therapeutic effectiveness of levosulpiride associated with omeprazole versus omeprazole alone in the reflux esophagitis has been evaluated. Two groups, each of 9 patients, were investigated before and after therapy on a clinical ground and endoscopically. While no difference was shown in terms of macro and microscopic resolution, a better subjective relief was obtained in the group treated with the association levosulpiride-omeprazole.


Differing effects of alpha-difluoromethylornithine and CGP 40116 on polyamine levels and infarct volume in a rat model of focal cerebral ischaemia.

Focal cerebral ischaemia was induced in rats by occlusion of the left middle cerebral artery. Two days later, infarct volume was determined by magnetic resonance imaging and the concentrations of the polyamines putrescine (PU), spermine and spermidine by HPLC. In control (occluded) animals, PU levels were elevated in infarcted and non-infarcted areas of the left hemisphere. Treatment with the ornithine decarboxylase (ODC) inhibitor alpha-difluoromethylornithine, prevented the ischaemia-induced increase in tissue PU without affecting infarct volume. Conversely, administration of the N-methyl-D-aspartate (NMDA) receptor antagonist CGP 40116 decreased cortical infarction without changing the tissue content of PU. We conclude that there is no direct link between NMDA receptor activation and brain PU, or PU and post-ischaemic tissue damage, and that inhibitors of ODC are not cerebroprotective in this animal model of stroke.


Glutamate-induced ribosomal disaggregation and ultrastructural changes in rat cortical neuronal culture: protective effect of horse serum.

Differentiated primary cortical neuronal cultures of rat were exposed for 5 min to 0.1 and 1.0 mM glutamate. In cultures maintained in serum-free medium after glutamate exposure, ribosomes completely disaggregated and neurons died within 24 h already after 0.1 mM glutamate. Addition of 5% horse serum to the culture medium prevented both ribosomal disaggregation and neuronal death even after exposure to 1.0 mM glutamate. Glutamate toxicity in vitro requires removal of serum-associated growth factors from the incubation medium and, therefore, may not be representative for neuronal vulnerability in vivo.


Lesions of nigrostriatal pathway reduce expression of tyrosine hydroxylase gene in residual dopaminergic neurons of substantia nigra.

The effects of unilateral mechanical transection of the nigrostriatal bundle of rat brain on the level of tyrosine hydroxylase (TH) mRNA and on the activity of TH enzyme in the substantia nigra (SN) were examined. Lesions resulted, by 14 days, in reductions of TH mRNA level to 10% of control and of TH enzyme activity to 39% of control in the ipsilateral SN. The percentage of TH mRNA is lower than either the percentage of surviving dopaminergic neurons or the remaining TH enzyme activity. In situ hybridization analyses also demonstrated the reduction of TH mRNA concentration in surviving dopaminergic neurons in the ipsilateral SN.


Elicitation of penile erection following activation of the hippocampal formation in the rat.

We explore the possible involvement of the hippocampal formation in penile erection, using male, adult Sprague-Dawley rats that were anesthetized with pentobarbital sodium. The intracavernous pressure (ICP) was used as the experimental index for penile erection. Electrical activation of the hippocampal formation resulted in two patterns, viz, multiple and single episodes of elevation in ICP, along with visible penile erection and ejaculation. The former pattern exhibited an increase in ICP that was more sustained, with higher peak amplitude and longer latency. Furthermore, they originated respectively from the granule cells of the dentate gyrus and pyramidal cells of the CA1 and CA3 fields of the Ammon's horn. Chemical stimulation of the hippocampus with glutamate also elicited significant increase in ICP. These results thus provided direct evidence to establish that the hippocampal formation may be involved in central neural regulation of the erectile process.


Apamin reduces the late afterhyperpolarization of lamprey spinal neurons, with little effect on fictive swimming.

The role of the late afterhyperpolarization (late AHP) in the firing properties of lamprey spinal neurons was tested by bath application of apamin, a selective blocker of the sk calcium-dependent potassium current. Intracellular recordings of identified motoneurons and interneurons were made with micropipette electrodes in the isolated lamprey spinal cord. Apamin reversibly reduced the amplitude of the late afterhyperpolarization without affecting other aspects of the action potential or the resting potential. The firing frequencies of the neurons were enhanced by apamin over a range of depolarizing current pulse injections. The effect of apamin was also tested on fictive swimming, which was induced in the isolated spinal cord by bath application of an excitatory amino acid (D-glutamate or N-methyl-D,L-aspartate). A concentration of apamin (10 microM) sufficient to substantially reduce the late AHP had no significant effect on the ventral root burst rate, intensity, or phase lag during fictive swimming.


Excitatory amino acid receptors involved in primary afferent-evoked polysynaptic EPSPs of substantia gelatinosa neurons in the adult rat spinal cord slice.

Intracellular recordings were made from substantia gelatinosa (SG) neurons in spinal cord slices to determine a subclass of excitatory amino acid receptors involved in polysynaptic excitatory postsynaptic potentials (EPSPs). In the majority of neurons, polysynaptic EPSPs evoked by A delta fiber were not affected by 2-amino-5-phosphonovaleric acid (APV), while all EPSPs including monosynaptic EPSPs were depressed by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). All spontaneous EPSPs were blocked by CNQX, while spontaneous EPSPs in a few SG neurons were attenuated by APV. These observations suggest that polysynaptic EPSPs evoked through A delta fibers are predominantly mediated by activation of the non-N-methyl-D-aspartate (non-NMDA) receptor subclass.


Expression of the dopaminergic phenotype in the olfactory bulb: neither calcitonin gene-related peptide nor olfactory input is necessary.

In the olfactory bulb, expression of tyrosine hydroxylase (TH) in juxtaglomerular neurons is dependent on innervation by the olfactory nerve. The presence of the neuropeptide calcitonin gene-related peptide (CGRP) within the olfactory nerve has led to the hypothesis that CGRP is responsible for regulation of TH expression in the bulbar neurons. On the other hand, other investigators claim that olfactory receptors never produce CGRP and that functional contact with olfactory axons regulates production of TH by bulbar neurons. Two different experimental procedures were used to test whether either CGRP or contact with the olfactory nerve is essential for production of TH by bulbar neurons in vivo. The peptidergic innervation of the olfactory bulb was eliminated either by neonatal capsaicin treatment, or by stereotaxic, electrolytic lesions of the ophthalmic division of the trigeminal nerve. Both of the treatments leave the olfactory innervation of the bulb intact while eliminating the CGRP-immunoreactive fibers in the olfactory nerve and glomeruli. Subsequent immunocytochemistry reveals a normal complement of bulbar TH-immunoreactive juxtaglomerular neurons in the absence of peptidergic innervation. In order to test whether olfactory nerve input is necessary for expression of TH in vivo, the anlage of the olfactory bulb was removed from embryonic (E16) rat pups and transplanted into the anterior chamber. These ectopic olfactory bulbs, although devoid of olfactory nerve input, contain numerous TH-immunoreactive neurons. Thus olfactory nerve input is not necessary for expression of TH in bulbar neurons.


Quisqualic acid-induced neurotoxicity is protected by NMDA and non-NMDA receptor antagonists.

Quisqualic acid-mediated excitotoxicity has been attributed essentially to the activation of non-N-methyl-D-aspartate (non-NMDA) receptors. In the present study we demonstrate the possible involvement of both NMDA and non-NMDA receptors in quisqualic acid-induced toxicity in mouse brain slices, in vitro. Incubation of mouse brain sagittal slices with various concentrations of quisqualic acid resulted in significant increase in the leakage of lactate dehydrogenase and potassium from the slices into the medium. Prior incubation of mouse brain slices with NMDA (MK-801 or AP7) or non-NMDA receptor antagonists (GDEE or quinoxalinediones) protected against quisqualic acid-mediated toxicity. Slices prepared from animals pretreated in vivo with MK-801 (5 mg/kg b.wt.) were also resistant to the toxic effects of quisqualic acid, indicating the possible involvement of NMDA receptors in quisqualic acid toxicity.


Neuropeptide FF is colocalized with catecholamine-synthesizing enzymes in neurons of the nucleus of the solitary tract.

Neuropeptide FF (NFF) is an amidated octapeptide of bovine origin. It has some antiopioid-like effects and it elevates blood pressure when injected intravenously in rats. NFF-immunoreactive nerve cells and terminals are localized in large numbers in the dorsomedial caudal brainstem which is a region involved in central regulation of blood pressure. We compared the localization of NFF-immunoreactive neurons with medullary catecholamine-synthesizing neurons by using immunohistochemical double-labeling and light microscopic mirror methods. NFF and tyrosine hydroxylase coexisted in a minor portion of the NFF neurons in the nucleus of the solitary tract and occasional cell bodies were stained with both NFF and PNMT (phenylethanolamine N-methyltransferase) antisera. The results have anatomical correlation with previous pharmacological reports, suggesting that NFF is present in neuronal systems involved in cardiovascular reflex arcs.


A novel inhibitor of glutamate release reduces excitotoxic injury in vitro.

Excessive release of glutamate has been implicated in the pathogenesis of excitotoxic neurologic disorders, such as stroke. BW 1003C87, an inhibitor of glutamate release and a putative Na+ channel antagonist, reduced veratridine-stimulated, tetrodotoxin- and dizocilpine-sensitive toxicity (measured by lactate dehydrogenase efflux) in neuron-enriched cortical cultures (IC50 = 5 microM). In contrast, BW 1003C87 (300 microM) had no effect on toxicity induced by direct application of 1 mM glutamate or 1 mM N-methyl-D-aspartate, or by depolarization with 50 mM KCl. Glutamate release inhibitors such as BW 1003C87 may provide a novel approach to protection from excitotoxicity.


Production of specific antibody against L-dopa and its ultrastructural localization of immunoreactivity in the house-shrew (Suncus murinus) lateral habenular nucleus.

An antiserum was raised against L-DOPA bound to bovine serum albumin, purified by affinity chromatography, and its specificities were verified by immunoblotting and enzyme-linked immunosorbent assays. The antiserum did not cross-react with dopamine (DA), tyrosine, tyramine, octopamine, norepinephrine or epinephrine. Immunocytochemical studies using the PAP method revealed that tyrosine hydroxylase- and L-DOPA positive but aromatic L-amino acid decarboxylase- and DA-negative neurons were present in the lateral habenular nucleus of the house-shrew (Suncus murinus) brain. Ultrastructurally L-DOPA immunoreactive products were localized in the cytoplasmic matrix and terminals with vesicles.


EPSPs in rat neocortical pyramidal neurones in vitro are prolonged by NMDA receptor-mediated currents.

We investigated the influence of 2-amino-5-phosphonovalerate (APV), a selective antagonist of the N-methyl-D-aspartate (NMDA) receptor, on the time course of small excitatory postsynaptic potentials (EPSPs) in pyramidal neurones in layer 2/3 of adult rat visual cortex in vitro. Time constants of the voltage decay following the EPSPs (T(s)) and after brief (2 ms) pulses of current injected at the soma (T(p)) were determined from semilogarithmic plots of averages of 100-250 trials. The mean T(s)/T(p) ratio decreased from 1.53 +/- 0.29 (S.D.) to 1.10 +/- 0.08 on addition of 50 microM APV to the bathing medium (P less than 0.001; n = 23), but there was no significant change in EPSP peak amplitude or rise-time. These results suggest that the time course of many small EPSPs, even at negative membrane potentials and in the presence of Mg2+, can be prolonged by NMDA receptor-mediated currents.


Effects of hexamethonium on transmitter release from the rat phrenic nerve.

Hexamethonium (HEX) was applied to isolated transected diaphragm-phrenic nerve preparations of the rat in order to further elucidate the functional role of the presynaptic nicotinic autoreceptors. End-plate potentials (EPPs) and miniature end-plate potentials (MEPPs) were recorded from the neuromuscular junctions in the presence and absence of HEX to determine the relative effect of this nicotinic antagonist on end-plate sensitivity and evoked release. In this study we show that HEX enhances transmitter release for the first few stimuli, but this action is not maintained during a train-of-six stimulation. While these results support the hypothesis that transmitter released from the nerve terminal normally has a negative feedback effect by depressing transmitter release it is proposed that HEX also has secondary actions on the neuromuscular junction that are unrelated to autoreceptor blockage. The results with HEX suggests that the presynaptic receptors may differ pharmacologically from the postsynaptic receptors.


Excitatory synaptic transmission mediated by NMDA and non-NMDA receptors in the superficial/middle layers of the epileptogenic human neocortex maintained in vitro.

Conventional intracellular recordings were made from regular-spiking cells located in layers II-IV to examine the involvement of excitatory amino acid receptors in synaptic transmission in epileptogenic human neocortical slices maintained in vitro. Extracellular stimuli that were below the threshold for generating action potentials evoked an excitatory postsynaptic potential (EPSP) with short latency to onset (0.8-4 ms). When suprathreshold stimuli were delivered, 95% of the neurons fired a single action potential. In 5% of the population, however, an all-or-none bursting discharge was observed. The EPSP and the bursting discharge were tested with the N-methyl-D-aspartate (NMDA) antagonist 3-((+/-)-2-carboxypiperazin-4-yl)propyl-1-phosphonate (CPP, 5 microM) or the non-NMDA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 4 microM). In the presence of CNQX the peak amplitude of the EPSP was reduced by 85% and the bursting discharge was abolished completely. By contrast, CPP reduced the peak amplitude of the EPSP by 52%, attenuated the late phase of the bursting discharge and increased its threshold. These results indicate that excitatory amino acids function as excitatory transmitters in the human brain. While the involvement of non-NMDA receptors in the EPSP is in line with data from normal neocortical slices of other mammals, the participation of NMDA-mediated conductances to the EPSP appears peculiar to the epileptogenic human neocortex. This evidence, together with the contribution of NMDA and non-NMDA receptors to the all-or-none bursting discharge suggests that excitatory amino acid-mediated transmission might be modified in the epileptogenic human neocortex.


Inhibition by locus coeruleus on the baroreceptor reflex response in the rat.

We evaluated the modulation of baroreceptor reflex (BRR) response by locus coeruleus (LC) in adult, male Sprague-Dawley rats anesthetized with urethane (1.5 g/kg, i.p.). Under an electrical stimulation condition that did not appreciably alter the basal systemic arterial pressure and heart rate, the LC significantly suppressed the BRR response. Microinjection of L-glutamate (1 nmol, 50 nl) into the LC essentially duplicated this depressant effect. Intracerebroventricular (i.c.v.) administration of the alpha 1-adrenoceptor antagonist, prazosin (6.5 nmol), appreciably blunted the inhibition by LC on the BRR response. Yohimbine (6.5 nmol), the alpha 2-adrenoceptor blocker, however, was ineffective. Direct microinjection of prazosin (50 pmol), but not yohimbine (50 pmol), into the terminal site of baroreceptor afferents at the nucleus tractus solitarii (NTS) also significantly blunted the suppressive effect of LC on the BRR response. These results suggest that the LC may produce an inhibition on the BRR response by a process that involves the alpha 1-adrenoceptors located in the NTS.


Expression of c-fos protein in the medulla oblongata of conscious rabbits in response to baroreceptor activation.

Neuronal expression of c-fos protein (Fos) in the medulla in response to baroreceptor activation was studied in conscious rabbits. Raising arterial pressure resulted in a marked increase, compared to control animals, in Fos immunoreactivity in the nucleus tractus solitarius, area postrema and ventrolateral medulla (VLM). Fos-immunoreactive neurons in the VLM extended from the level just rostral to the obex to 3 mm more caudal. Only a small proportion of these neurons showed tyrosine hydroxylase immunoreactivity. The results indicate that baroreceptor activation induces Fos expression in circumscribed medullary regions which have previously been shown to receive excitatory baroreceptor inputs.


Aluminum inhibits glutamate release from transverse rat hippocampal slices: role of G proteins, Ca channels and protein kinase C.

Aluminum (Al) has been shown to produce deficits in learning and memory. The present experiments tested the hypothesis that Al-induced inhibition of learning may be due to its effect on glutamate release secondary to changes in calcium channel function and/or intracellular events triggering glutamate release. Calcium-dependent potassium (K)-evoked [14C]-glutamate release from 400 microns transverse rat hippocampal slices was inhibited by Al in a concentration dependent manner (IC50 = 40 microM). Aluminum (30, 100 microM) noncompetitively inhibited Bay K 8644-evoked glutamate release. 4-Aminopyridine (30, 1000 microM) noncompetitively attenuated the Al inhibition of glutamate release, suggesting an Al-induced alteration of Ca channel function. Activation of the Gi protein by R(-)phenylisopropyladenosine (PIA; 1 microM) reduced K-evoked glutamate release 69%, whereas 300 microM Al produced an 84% reduction. These effects were prevented by the Gi protein inhibitor N-ethylmaleimide (NEM; 100 microM), suggesting an effect of Al on the Gi protein to inhibit glutamate release. Phorbol myristate acetate (0.16 microM)-induced glutamate release was inhibited by 300 microM Al and 80 microM polymyxin B, suggesting an Al modulation of protein kinase C (PKC)-evoked glutamate release. These results demonstrate an Al inhibition of glutamate release that may be mediated by multiple, but interconnected mechanisms (e.g., via interactions with Ca systems), providing multiple targets for an Al-induced alteration of neuronal function.


Dynorphin A content in the rat brain and spinal cord after a localized trauma to the spinal cord and its modification with p-chlorophenylalanine. An experimental study using radioimmunoassay technique.

The distribution of dynorphin A in the spinal cord and brain of normal rats and of rats subjected to a focal injury of the spinal cord was examined in a rat model using a radioimmunoassay (RIA) technique. The validity of RIA was checked by high performance liquid chromatography (HPLC). Furthermore, the possibility that the peptide is somehow functionally related with endogenous 5-hydroxytryptamine (5-HT, serotonin), was also evaluated using a pharmacological approach. In normal animals, the peptide content was very similar in the spinal cord segments (T9, T10-11, and T12) examined whereas, the dynorphin content of the whole brain was about two-fold higher compared with that in the spinal cord. A focal injury to the spinal cord in the right dorsal horn (about 1.5 mm deep, 2.5 mm long and 1.5 mm to the right of the midline) of the lower thoracic cord (T10-11) in urethane anaesthetised animals significantly altered the peptide content in the whole brain as well as in the spinal cord. Thus, a decrease in the peptide level in whole brain, T10-11 and in the T12 segments of the spinal cord was observed 1 and 2 h after trauma. At 5 h, the peptide had accumulated markedly in the T9 segment (about a two-fold increase) as compared with the controls. At this time, the peptide content had been restored in the T10-11 and T12 segments. On the other hand, the whole brain dynorphin level continued to remain low (by 55%) as compared to the control group.(ABSTRACT TRUNCATED AT 250 WORDS)


Extrapyramidal symptoms are serious side-effects of antipsychotic and other drugs.

Antipsychotic medications commonly produce extrapyramidal symptoms as side effects. The extrapyramidal symptoms include acute dyskinesias and dystonic reactions, tardive dyskinesia, Parkinsonism, akinesia, akathisia, and neuroleptic malignant syndrome. Extrapyramidal symptoms are caused by dopamine blockade or depletion in the basal ganglia; this lack of dopamine often mimics idiopathic pathologies of the extrapyramidal system. Less recognized is that extrapyramidal symptoms are also associated with certain non-antipsychotic agents, including some antidepressants, lithium, various anticonvulsants, antiemetics and, rarely, oral-contraceptive agents. Extrapyramidal symptoms caused by these agents are indistinguishable from neuroleptic-induced extrapyramidal symptoms. Clinicians must be able to recognize these side effects and be able to determine the antipsychotic-induced and non-antipsychotic causes of extrapyramidal symptoms.


Localization of alpha-2 adrenergic receptors in the human eye.

To elucidate sites of the action of alpha-2 adrenergic drugs, we localized binding sites for a potent alpha-2 adrenergic agonist, UK-14,304, in sections of the human cadaveric eye by an in vitro ligand-binding technique and autoradiography. Its specific binding sites were found in the iris epithelium and ciliary epithelium at a high level, and also in the ciliary muscle, retina, retinal pigment epithelium (and/or choroid). Binding of UK-14,304 to the ocular pigments was prevented by preincubating the eye sections with chloroquine, which reduced the non-specific binding to a low level.


Simple and accurate assay for tyrosine hydroxylase from bovine retina by high-performance liquid chromatography with fluorescence detection.

We present a simple and sensitive assay for tyrosine hydroxylase (TH) using high-performance liquid chromatography (HPLC) with a fluorescence detector which enabled us to study bovine retinal TH of a small quantity in crude retinal samples. The detection limit with this method was 1 pmol of dihydroxyphenylalanine (DOPA) enzymatically produced. Retinal TH exhibited the maximum activity at pH 6 to 6.3, and almost none at physiological pH of above 7, a tendency similar to that reported for striatal TH.


Contraindications to vasoconstrictors in dentistry: Part III. Pharmacologic interactions.

This article discusses the relative contraindications to the use of vasoconstrictor in patients currently medicated with tricyclic antidepressants, monoamine oxidase inhibitors, phenothiazines and beta-blockers. It reviews drug interactions and emphasizes potential detrimental systemic effects that epinephrine contained in local anesthetics can have when administered concomitantly with these drugs. Finally, special considerations are expressed concerning patients who abuse illicit drugs such as cocaine.


[Ocular manifestations in porphyria cutanea tarda].

Ninety two patients suffering from porphyria cutanea tarda were examined ophthalmologically in a paired case-control study. The incidence of pinguecula and that of pterygium were 8 times and 2 times higher, respectively, in PCT patients that in the control group. The photodamage of the conjunctiva is presumed to be a result of the photoactivity of uroporphyrin in the tissues.


[Effectiveness and safety of long-term H2-receptor antagonist maintenance therapy].

The long-term maintenance therapy with an H2 receptor antagonist is currently the best treatment for ulcer disease. The treatment is effective in keeping most ulcers in remission, and is safe both by preventing ulcer complications and because the treatment itself is innocuous. Maintenance therapy achieves the objective of all treatment--it restores patients to normal health. Treatment of ulcer disease with an H2 receptor antagonist can be considered one of the triumphs of modern therapy.


HTLV-I and HTLV-II tax trans-activate the human EGR-1 promoter through different cis-acting sequences.

The immediate-early response gene, EGR-1, encodes a zinc finger-containing transcription factor that is involved in growth and differentiation of a variety of cell types. EGR-1 is induced in normal T cells following mitogenic stimulation and has recently been shown to be constitutively expressed in human T-cell leukemia virus type I (HTLV-I)- and type II (HTLV-II)-transformed T-cell lines. The trans-activating protein of HTLV-I, Tax, has been demonstrated to trans-activate promoters of a number of cellular genes, some of which may be critical in regulating T-cell proliferation. In this study, we examine the effect of Tax on expression of EGR-1 in three T-cell lines and demonstrate that both HTLV-I and -II Tax are capable of trans-activating human EGR-1 recombinant promoter constructs. Interestingly, HTLV-I and -II Tax trans-activate the human EGR-1 promoter through different promoter regions in the Jurkat cell line, suggesting that HTLV-I and -II Tax may lead to constitutive expression of EGR-1 through different signaling pathways. Deregulated expression of EGR-1 may contribute to uncontrolled cell growth and transformation during early stages of T-cell activation in HTLV-I and -II-infected cells.


p53 mosaicism with an exon 8 germline mutation in the founder of a cancer-prone pedigree.

Changes in the tumor-suppressor gene p53 are frequently acquired during the course of malignant development of human tumors. Recently, constitutional heterozygous mutations in p53 exon 7 have been identified as the primary cause of cancer predisposition in cases of the familial Li-Fraumeni cancer syndrome. These findings underline the need for extensive mutation screening in families with high cancer incidence. This report describes the detection and follow-up by two-dimensional single-strand conformation polymorphism analysis (2DSSCP) of a new germline mutation of p53 exon 8 in a case of suspected Li-Fraumeni syndrome. Although a high cancer incidence had been reported in the family history of the father of siblings suffering from brain tumor and rhabdomyosarcoma, a constitutional heterozygous p53 mutation was identified only in the affected children. Retrospective analysis of archival tissue of a half-sister who died several years ago from a tumor of previously uncertain diagnosis revealed the same mutation. The mutation had therefore occurred in the germ cells of the mother, who thus appears to be a mosaic. The cancer predisposition of the paternal ancestors must have been due to other factors.


The insulin-like growth factor 1 receptor is required for the proliferation of hemopoietic cells.

We have investigated the role of the insulin-like growth factor one (IGF1) receptor and its relationship to the proto-oncogene c-myb in the growth of two types of hemopoietic cells: mitogen-stimulated human peripheral blood mononuclear cells and a human promyelocytic cell line (HL-60). Using the antisense strategy and the reverse transcriptase polymerase chain reaction (RT-PCR), we show that expression of the IGF1 receptor is required for the entry into S phase of both stimulated lymphocytes and HL-60 cells. The inhibition of DNA synthesis by antisense oligomers to the IGF1 receptor RNA is accompanied by an inhibition of the expression of the mRNA for a DNA synthesis gene, proliferating cell nuclear antigen (PCNA), the co-factor of DNA polymerase delta. Inhibition of c-myb expression results in a decrease in IGF1 receptor mRNA levels; on the other hand, inhibition of IGF1 receptor expression has no effect on c-myb mRNA levels. A tentative temporal relationship between these three genes (c-myb, IGF1 receptor, PCNA) is proposed.


Mechanisms of c-erbB2/neu oncogene-induced metastasis and repression of metastatic properties by adenovirus 5 E1A gene products.

c-erbB2/neu is a transforming oncogene that encodes a 185-kDa transmembrane glycoprotein. In many but not all studies, amplification and/or overexpression of the human c-erbB2/neu oncogene has been correlated with poor prognosis and the number of lymph node metastases in node-positive breast cancer patients. We have shown that expression of the activated rat c-erbB2/neu oncogene in mouse embryo fibroblast 3T3 cells is sufficient to induce experimental metastases in nude mice. Important steps in the metastatic event are tumor cell adhesion to endothelial cells and invasion of basement membranes. Therefore, we further examined the ability of c-erbB2/neu oncogene-transformed 3T3 cells to adhere to microvessel endothelial cells and secrete basement membrane-degradative enzymes. The c-erbB2/neu oncogene-transformed 3T3 cells were shown to be more adherent and have higher gelatinase activities. Since we had previously shown that the adenovirus 5 E1A gene product can suppress c-erbB2/neu-induced transformation of 3T3 cells, we examined the possibility that E1A can abrogate the metastatic properties of c-erbB2/neu-transformed 3T3 cells. We found that introduction of the E1A gene into c-erbB2/neu-transformed 3T3 cells reduced the formation of experimental metastatic tumors and inhibited metastasis-associated properties, such as adhesion to microvessel endothelial cells, migration through a layer of reconstituted basement membrane (Matrigel) and secretion of basement membrane-degradative enzymes. The results indicate that the mechanism by which the c-erbB2/neu gene induces higher metastatic potential is to promote adhesion and invasion steps of the metastatic cascade. The E1A gene, which functions by inhibiting these steps, is thus a suppressor gene for c-erbB2/neu-induced experimental metastasis.


[Stress related immune regulation].

The immune system ist capable of producing factors, which apart from playing a crucial role during the immune response, serve to integrate immune-neuroendocrine circuits with immunoregulatory and metabolic consequences for the organism. Hormones and neuropeptides on the other hand exert direct effects on immune cells via specific surface receptors on such cells. Therefore, there is strong evidence for a bidirectional communication between the immune, endocrine, and central nervous systems mediated by peptide hormones and receptors common to these systems. One element of the immune system's response to stress factors may involve the activation of the hypothalamo-pituitary-adrenal axis and other neuroendocrine circuits. A complex network of neuroendocrine immune systems is able to sustain biologic adaptation and homeostasis in response to stresses and needs to be taken into account in every clinical context of stress responses.


Identification and quantification of rodent malaria strains and species using gene probes.

A DNA probe PCsv4 and a subclone thereof PCsv4.1, hybridize specifically to rodent malaria DNA. DNA purified from a small volume (10 microliters) of infected mouse blood was used to determine the composition of the parasite population present. The hybridization signal following PCsv4 probing of slot-blotted DNA correlated directly with parasitaemia. The hybridization pattern and intensity, resulting from probing restriction enzyme digested and Southern-blotted genomic DNA, determined the identity of the infecting parasite line(s), and provided a semi-quantitative measure of parasite burden. Fifteen parasite lines representative of all four Plasmodium species infecting rodents can be differentiated in this way.


[Molecular genetics and prenatal diagnosis].

Recombinant DNA techniques have provided new insight into genetic and prenatal diagnosis during the last 10 years. Human gene mapping data are increasing exponentially due to molecular biology advances. Most analyses are possible from chorionic villi biopsy specimens as early as the 10th week of fetal life. When the gene is known and cloned, the diagnosis is regularly made by using the polymerase chain reaction technique; when the gene is unknown but mapped, the restriction fragment length polymorphism technique is used. However, these methods for prenatal assessment require a reliable diagnosis of index case disease and a preliminary familial DNA study.


A drug use review study in patients with obstructive lung disease. Assessment of the quality of drug therapy.

This study presents the results of an analysis of the pharmacy records of 778 patients with asthma or chronic obstructive lung diseases. The high percentage of patients taking oral corticosteroids was striking. Inhaled beta-agonists for use as needed have been prescribed to only a minority of patients using these agents. Only half of the patients on beta-agonists used inhaled corticosteroids prophylactically. Drug interactions capable of causing changes in plasma theophylline concentrations appeared in only a small number of patients. The results from studies like the one presented here can provide valuable data to be used for further discussion between physicians and pharmacists about rational drug therapy.


PCNA-induced DNA synthesis past cis-syn and trans-syn-I thymine dimers by calf thymus DNA polymerase delta in vitro.

Calf thymus proliferating cell nuclear antigen (PCNA) promoted DNA synthesis past cis-syn and trans-syn-I cyclobutane thymine dimers by calf thymus DNA polymerase delta (Pol delta) in vitro. Templates containing site-specific cis-syn and trans-syn-I thymine dimers were prepared via a combination of solid phase synthesis with photoproduct building blocks and DNA ligation. Extension of a 15-mer primer on the UV dimer-containing templates by Pol delta produced termination and bypass products in a dNTP and PCNA dependent manner. In the absence of PCNA and at dNTP concentrations varying between 1 and 100 microM, Pol delta could not bypass the cis-syn dimer and terminated elongation one nucleotide prior to the 3'-T of the dimer. DNA synthesis past the trans-syn-I dimer was even less efficient. In the presence of PCNA, termination occurred primarily one nucleotide prior to the 3'-T of both dimers at 1 microM dNTPs but opposite the 5'-T of the dimers at 100 microM dNTPs. In addition, under the latter conditions, bypass of the dimers was observed, to the extent of about 30% of the products for the cis-syn dimer and about 15% for the trans-syn-I dimer.


The sustained development of preneoplastic lesions depends on high protein intake.

The effects of sequential alterations in the feeding of two levels of dietary protein (5% and 20% casein) on the postinitiation development of aflatoxin B1- (AFB1) induced gamma-glutamyl transpeptidase-positive (GGT+) preneoplastic foci were examined. Weanling male Fischer 344 rats fed AIN-76A diet (20% protein) were administered 10 intragastric doses of AFB1 (1 dose/day during the 14-day dosing period excluding weekends) at 250 micrograms/kg body wt (initiation). After AFB1 tissue clearance, rats were randomly assigned to dietary treatment groups. During the next 12 weeks (promotion), they developed AFB1-induced GGT+ preneoplastic lesions. The 12-week promotion period was subdivided into four three-week periods, during which rats were fed isocaloric diets containing 20% casein during all four periods (20:20:20:20), 5% casein during all four periods (5:5:5:5), or sequentially altered casein levels (20:5:20:5 and 5:20:5:20). Rats were killed at 3,6,9, and 12 weeks to examine the dependence of GGT+ foci development on protein intake. Animals fed 5% casein diets developed significantly fewer (p < 0.01) GGT+ foci than animals fed 20% casein diets despite greater total caloric intake. Similarly, in the intervention groups, preneoplastic development was enhanced when the 20% casein diet was fed and inhibited when the 5% casein diet was fed. These results indicate that the sustained development of AFB1-induced preneoplastic foci depends on a high protein intake. Alternatively, these results suggest that low protein intake inhibits lesion development.


Isolation of a novel tetrapeptide with opiate and antiopiate activity from human brain cortex: Tyr-Pro-Trp-Gly-NH2 (Tyr-W-MIF-1).

A novel tetrapeptide, Tyr-Pro-Trp-Gly-NH2 (Tyr-W-MIF-1), was purified from extracts of frontal cortex of human brain tissue by several consecutive reversed-phase high performance liquid chromatographic steps followed by a radioimmunoassay originally developed for Tyr-Pro-Leu-Gly-NH2 (Tyr-MIF-1). Sequencing, mass spectrometric analysis, and comparison of its chromatographic behavior with that of the synthetic peptide confirmed the structure. Like Tyr-MIF-1, which was previously isolated from human brain tissue, Tyr-W-MIF-1 can inhibit the binding of 3H-DAMGO (selective for mu opiate receptors) to rat brain and can act as an opiate agonist as well as antagonist. Tyr-W-MIF-1 was a more potent opiate agonist than Tyr-MIF-1, the free acid of Tyr-W-MIF-1, and the structurally related hemoglobin-derived opiate peptide hemorphin-4 (Tyr-Pro-Trp-Thr) in the guinea pig ileum. Each of these peptides acted as opiate antagonists on the ileum from morphine-tolerant guinea pigs; the free acid of Tyr-W-MIF-1 was the most potent antagonist in inhibiting the activity of DAMGO. The results demonstrate the presence in human brain of a new member of the Tyr-MIF-1 family of biologically active peptides.


Neuroanatomical connections between corticotropin-releasing factor (CRF) and somatostatin (SRIF) nerve endings and thyrotropin-releasing hormone (TRH) neurons in the paraventricular nucleus of rat hypothalamus.

In order to investigate the possible involvement of corticotropin-releasing factor (CRF) and somatostatin (SRIF) on thyrotropin-releasing hormone (TRH) neuronal cell activity in the rat hypothalamic paraventricular nucleus, we have proceeded to the simultaneous localization of CRF or SRIF and TRH. For this purpose, we used a dual immunostaining procedure that employed antibodies to CRF and SRIF and peroxidase-labeled goat anti-rabbit IgG as a first sequence, and antibodies to a cryptic fragment (Phe178-Glu199) of pro-TRH (to label TRH neurons) and alkaline phosphatase-labeled goat anti-rabbit IgG as the second sequence. A rich innervation of the paraventricular nucleus by immunoreactive CRF and SRIF fibers was observed. A large number of CRF and SRIF nerve endings were seen intimate anatomic proximity and often appeared to surround TRH-containing cell bodies. These results strongly suggest that TRH neurons might be regulated by both CRF and SRIF. These interactions might be the neuroanatomical basis for the already observed inhibitory effects of CRF and SRIF on TRH release.


Identification of neuropeptide-degrading enzymes in the pancreas.

Neutral endopeptidase (NEP) and aminopeptidase M (APM) were identified in the pancreas by enzymatic assays and Western blotting. The NEP activity, assessed by the phosphoramidon- and DL-thiorphan-inhibitable degradation of glutaryl-Ala-Ala-Phe-4-methoxy-2-naphthylamine, was 28.8 pmol/h/micrograms of pancreatic membrane protein and 124 pmol/h/10(6) pancreatic acinar cells. The APM enzymatic activity, assessed by the actinonin- and amastatin-inhibitable degradation of Ala-4-methoxy-2-naphthylamine, was 633 pmol/h/micrograms pancreatic membrane protein and 17.4 nmol/h/10(6) pancreatic acinar cells. Proteins corresponding to NEP (95 kDa) and APM (140 kDa) were identified in membranes by Western blotting. Both NEP and APM on acinar cells may degrade neuropeptides and regulate their effects on exocrine secretion.


Blockade of dynorphin A(1-13) overt psychomotor effects by naloxone.

Each of the dynorphin A(1-13) or dynorphin (dyn) treatment groups receiving naloxone showed a significant overall reduction of overt signs compared with the dyn controls. The data suggested that the overt psychomotor effects of dyn in the rhesus monkey were especially prone to blockade by naloxone, and probably involved opioid mechanisms.


[Migraine as one of the symptoms of food allergy].

A role of nutrients in the onset of migraine and other gastrointestinal symptoms (vomiting, nausea, diarrhoea), skin reactions (rush, atopic dermatitis, Quincke'a edema), respiratory symptoms (bronchial asthma, cough, allergic rhinitis, polyps, congestion of the nasal mucosa), motion system disorders (jointache and edema), gynecological disorders (chronic and recurrent adnexitis), and sleep disorders together with emotional tension and behavioral disturbances has been assessed in 17 patients with atopy. Migraine attacks have been produced most frequently by cow milk (in 10 out of 17 patients), cabbage, flour and eggs in 5 patients, preservatives, cottage and Swiss cheese, porcine meat in 4 patients, colorants and chocolate in 3 patients, beef, strawberries, lemons and butter in 2 patients. Other nutrients produced headache in single patients. Migraine and other symptoms have diminished after an individual elimination diet. Recurrence has been noted after each consumption of allergen except one female patient with EEG abnormalities. Immunoglobulins E have been involved in headache-producing mechanism in 3 patients.


Exercise and hypertension. Maximizing the benefits in patients receiving drug therapy.

Aerobic exercise may prevent hypertension and reduce blood pressure and mortality in hypertensive patients and those at high risk for coronary artery disease. Supervised aerobic exercise at an intensity of 70% to 80% of maximal aerobic capacity is recommended to achieve cardiovascular conditioning and other health benefits. When antihypertensive drug therapy is required, physicians should choose an agent that has favorable secondary effects, including hemodynamic responses to exercise. The most favorable effects are achieved with calcium channel blockers, angiotensin-converting enzyme inhibitors, alpha blockers, and central alpha agonists. The effects of diuretics are less desirable, and beta blockers should be a last choice for hypertensive patients who are physically active.


Asthma in the 1990s. A new approach to therapy.

Asthma has been shown to be an inflammatory disease. Therefore, it makes sense to base treatment strategies on the selection of an appropriate anti-inflammatory agent, with bronchodilators being used as effective rescue medications. Because of recent concerns raised in the literature about the safety of long-term use of beta 2 agonists, early and appropriate medication in the form of inhaled corticosteroids or cromolyn sodium is recommended for daily control of asthma symptoms, long-term patient management, and prevention of acute exacerbations.


[Current theories on the etiology and treatment of Gilles de la Tourette's disease].

Gilles de la Tourette syndrome is a condition marked by: (1) onset usually in childhood and adolescence, i.e. between 2 and 15 years of life; (2) violent facial tics and echolalia; (3) increased excitability and apathy; (4) progressive increase in symptoms intensity; (5) chronic course. This syndrome is threefold more frequent in men than in women. None hypothesis concerning its etiopathogenesis (genetic, organic, organic-functional, psychomotor, and mixed) does explain its origin. Many cases respond with some degree of relief to neuroleptics, carbamazepine, clonidine, and glucocorticosteroids. Neurosurgery and psychotherapy are also of value. Haloperidol is commonly considered the most effective in this syndrome.


[Use of molecular DNA probes in the diagnosis of mucoviscidosis-- analysis of restriction fragment length polymorphisms (RFLP) in 22 high-risk families].

The results of DNA analysis with the aid of specific molecular probes are discussed. DNA analysis involved 22 families of a high risk of cystic fibrosis. A significance of the obtained results in genetic counselling is also discussed. DNA analysis enabled detection or exclusion of cystic fibrosis gene carrier state in patient's relatives. DNA analysis proved fully informative in case of 17 families being a base to offer these families prenatal diagnosis of the disease in the I trimester of pregnancy, if such a family plans conception, and to accept this diagnostic technique.


Outpatient management of inflammatory bowel disease. Let's keep it as simple as possible.

Inflammatory bowel disease is a conglomeration of disorders of unclear etiology and pathogenesis. Confirming the diagnosis of active disease may be difficult but is critical to judicious therapy. Sulfasalazine (Azulfidine) and its newer derivatives mesalamine (Asacol, Rowasa) and olsalazine sodium (Dipentum) are used for treatment of mild disease and maintenance. Corticosteroid therapy controls moderate disease in most patients, but withdrawal may be difficult. Immunosuppression or surgery may be necessary in severe or refractory cases. The risk of cancer as a complication of inflammatory bowel disease is often exaggerated but cannot be ignored.


Effect of acute and chronic treatment of rats with the putative anxiolytic drug ipsapirone on the turnover of monoamine transmitters in various brain regions. A comparison with the 5-HT1A agonist 8-OH-DPAT.

A fourteen-days treatment (twice a day) of male Wistar rats with the putative anxiolytic ipsapirone (10 mg/kg po) and the selective 5-HT1A agonist 8-OH-DPAT (1 mg/kg ip) induced changes in the turnover of serotonin and catecholamines in various regions of the brain. In contrast to 8-OH-DPAT, ipsapirone stimulated the development of tolerance in serotonin neurons in the hypothalamus, hippocampus, cortex and striatum. Nevertheless, adaptative changes were not produced by ipsapirone in dopamine neurons in the striatum or nucleus accumbens, or in noradrenaline neurons in the hypothalamus, hippocampus or cortex. The centrally active metabolite of ipsapirone 1-PP, which has adrenolytic properties, seems to be responsible for the effects on the dopamine and noradrenaline turnover.


Structure-activity relationship studies of CNS agents. Part III. On the bioactive conformations of 1-arylpiperazines at 5-HT1A receptor.

Quantitative structure-activity relationships (QSAR) were analyzed for 5-HT1 and 5-HT1A affinity data of two series of 1-arylpiperazines. A conformational analysis of the investigated derivatives was performed using CNDO/2 method. It was shown that some 1-arylpiperazines adopt the bioactive conformations, while the others, like 1-(2-alkylphenyl)-piperazines, should exist in the twisted conformations at the receptor sites.


Pruritus. What to do when the itching won't stop.

Pruritus is a common problem that can result from many conditions. Some, such as fungal or parasitic infection, may be fairly obvious. However, others, such as iron deficiency and psychogenic disorder, are more difficult to diagnose. Evaluation must include a thorough inspection of the skin, history taking for drug intake and chemical exposure, and appropriate laboratory testing. The location on the body and characteristics of the itching may point to a cause. In some cases, attention to exacerbating factors (eg, dry skin, coarse fabrics against the skin, dry environmental conditions) and application of topical preparations may be sufficient. Antihistamines are the foundation of oral treatment, and with the advent of second-generation agents, they can be taken with fewer concerns about their sedative effects. Specific conditions of which pruritus is one feature may require specific treatment. For example, in patients undergoing dialysis, activated charcoal, UV light treatment, or heparin therapy may be useful.


The fate of altered hepatocytic foci as a result of treatment with oxodipine, a calcium channel blocker.

The dietary administration of the calcium channel blocker oxodipine to Fischer (F344) rats for 12 and 30 months resulted in increased incidence of altered hepatocytic foci (AHF). As the Environmental Protection Agency (EPA) regards AHF as potentially precancerous it is important to accumulate experimental evidence which may negate this theory. In the case of oxodipine we proved that with dosages close to maximum tolerated dose (MTD) for prolonged periods no hepatic neoplasms were produced. The possible nature of such AHF is discussed.