Phase-resetting effect of 8-OH-DPAT, a serotonin1A receptor agonist, on the circadian rhythm of firing rate in the rat suprachiasmatic nuclei in vitro.

The 5-HTergic neurons in the mesencephalic raphe nuclei provide a robust projection to the hypothalamic suprachiasmatic nucleus (SCN), the site of a putative neuronal circadian pacemaker. Although it has been suggested that 5-HT neurons may play a role in the circadian timing system, this role has not yet been specified. Prosser et al. (Brain Res., 534 (1990) 336-339) reported that 1 h treatments with quipazine induce robust phase shifts in vitro, and that this effect depends upon the circadian time of treatment. However, quipazine is a non-specific 5-HT agonist. Besides, it is reported that the 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino)tetraline hydrobromide (8-OH-DPAT) affected a circadian rhythm of hamster wheel-running activity. In the present study we investigated whether the 5-HT1A agonist 8-OH-DPAT can reset the phase of the SCN clock when it is isolated in vitro. The present results show that 1 h treatments with 8-OH-DPAT induce robust phase advances in vitro when it was administered during the subjective day. This result suggests that 5HT1A receptor functioning may play a role in modulating the phase of SCN clock, especially during the subjective day.


Effects of advancing age on cerebrospinal fluid concentrations of prolactin in the female rat.

Studies were conducted to determine the effects of advancing age on serum and cerebrospinal fluid (CSF) prolactin (PRL) concentrations in the female rat. In young rats with basal serum PRL levels, CSF PRL was maintained at 1.1-2.1% of serum PRL levels. In middle-aged rats, CSF PRL levels and the ratio of CSF to serum PRL was low in rats which maintained estrous cycles, but was increased 4- to 10-fold in rats which were in constant estrus. In aged constant estrous rats, CSF PRL concentrations were increased markedly and the CSF to serum PRL ratio increased to 31%. Collectively, these data indicate that (i) in young female rats, only a fraction of serum PRL reaches the CSF; (ii) that CSF PRL concentrations are low in middle-aged rats which exhibit estrous cycles and (iii) that aging and the constant estrous state are associated with elevated CSF PRL concentrations. As such, the age-related elevation in serum PRL levels and the fraction of PRL which accumulates in the CSF may contribute to the age-related dysfunction in brain PRL-responsive neurons.


Age-related changes in kynurenic acid production in rat brain.

Two separate in vitro assays were used to examine the biosynthesis of the broad spectrum excitatory amino acid receptor antagonist kynurenic acid (KYNA) during the life span of the adult rat. Assessment of KYNA's anabolic enzyme kynurenine aminotransferase revealed steady increases between 3 and 24 months of age in all five brain regions examined. No changes were observed in the liver. The changes were particularly pronounced in the cortex and in the striatum where enzyme activity increased three-fold during the period studied. KYNA production from its bioprecursor L-kynurenine was also investigated in tissue slices and was found to be significantly enhanced in the cortex and hippocampus of old animals. The effect of depolarizing agents or sodium replacement was virtually identical in tissues from young and old rats. These data, which are in excellent agreement with reports on an age-dependent increase of KYNA concentration in brain tissue, suggest an enhanced KYNA tone in the aged brain. Together with the reported decline in cerebral excitatory amino acid receptor densities with age, increased production of KYNA may play a role in cognitive and memory dysfunction in old animals.


Monoaminergic uptake in synaptosomes prepared from frozen brain tissue samples of normal and narcoleptic canines.

Canine narcolepsy, a model of the human disorder, is associated with altered catecholamine but not serotonin (5-HT) metabolism in some brain areas, particularly the amygdala. A possible explanation for these global changes could be the existence of specific defects in monoamine uptake processes. We have studied the uptake of [3H]norepinephrine (NE), [3H]dopamine (DA) and [3H]5-HT in synaptosomes prepared from cortex and amygdala of narcoleptic and control Doberman pinscher brains. Since narcoleptic canines are relatively few in number, we have used a specific brain freezing procedure that has been reported to allow restoration of metabolically functional tissue upon thawing. Preliminary studies comparing monoamine uptake in fresh and frozen brain samples of both groups of dogs were carried out and demonstrated that this procedure significantly altered serotoninergic but not noradrenergic and dopaminergic uptake. All further investigations were then done on synaptosomes prepared from frozen samples. Our results demonstrate that synaptosomal uptake of [3H]NE, [3H]DA and [3H]5-HT in cortex and amygdala are not altered in narcolepsy.


A two-trial memory task with automated recording: study in young and aged rats.

A two-trial recognition task, based on place or object exploration in a Y-maze, was developed to study memory in adult and aged rats. This paradigm avoids the use of electric shocks or deprivation that may have non-specific influences on the responses, and the task does not require learning of a rule. A number of behavioral parameters in several animals could be recorded automatically. These behavioral parameters were found to be differently influenced both by the type of recognition (place vs. object) and by the inter-trial interval (recognition retention time). Impaired recognition was also detected in 18-months-old rats. This recognition task which combines simplicity, sensitivity and high specificity may thus be a useful adjunct to our current battery of memory tasks.


The oligemic phase of cortical spreading depression is not blocked by tirilazad mesylate (U-74006F).

Cortical spreading depression is characterised by a wave of depolarization that moves across the cortex leaving in its wake a state of hyperpolarization. Characteristic changes in cerebral blood flow are also seen and these consist of a wave of hyperemia followed by an oligemia, the latter lasting some hours in some experimental animals including the cat. In this study cerebral blood flow was measured using laser Doppler flowmetry in the anesthetised ventilated cat. Spreading depression was initiated with a pin-prick injury prior to or following administration of U74006F (tirilizad mesylate; 3 mg/kg, ivi) or an identical volume of vehicle. Laser Doppler probes were placed bilaterally and in each case studied both the hyperemic and oligemic phases of spreading depression were preserved after administration of either U74006F or its vehicle. These data suggest that free radical mechanisms have no significant role in mediating the blood flow changes of spreading depression and are consistent with data in the literature of a quantitative using single-point measurements that again U74006F does not affect spreading depression.


Pain-related increases in spinal cord membrane-bound protein kinase C following peripheral nerve injury.

Neuropathic pain following nerve injury is thought to involve central nervous system Ca(2+)-mediated neuronal plastic changes. This study provides evidence that induction and/or maintenance of post-injury neuropathic pain behaviors in the rat is associated with increases in membrane-bound protein kinase C (PKC), a Ca(2+)-dependent process known to mediate central nervous system neuronal plasticity. In addition, spinal cord administration of GM1 ganglioside, an intracellular inhibitor of PKC translocation/activation, reverses both increased levels of membrane-bound PKC and pain-related behaviors. Thus, persistent post-injury neuropathic pain may be mediated by the initiation of excitatory neuropathological processes resulting from an increase in membrane-bound PKC.


Reduction of hibernation bout duration by intraventricular infusion of met-enkephalin.

The potential of brain met-enkephalin (met-enk) systems to modulate central nervous system (CNS) activity during periods of general depression (modeled by the mammalian hibernation state) was studied in the ground squirrel (Citellus lateralis). Following entrance into hibernation, continuous met-enk infusion into the lateral ventricle (1 microliter/h; 0.2, 1 and 5 micrograms/microliter) produced a dose-dependent reduction in bout duration ranging from 1.2 to 3.9 days (13.8-44.6% of baseline bout duration). We suggest that the activity of met-enk-releasing neurons may serve to increase the excitability of the depressed CNS, thus accelerating the termination of the hibernation bout.


Scopolamine attenuates haloperidol-induced c-fos expression in the striatum.

Haloperidol increases the expression of Fos, the protein product of the proto-oncogene c-fos, in some parts of the central nervous system. Haloperidol also produces catalepsy in rodents and extrapyramidal side effects in humans, both of which are reduced by muscarinic receptor antagonists. In order to gain insight into the neurochemical and neuroanatomical substrates of haloperidol-induced catalepsy we examined the effects of the muscarinic receptor antagonist scopolamine on haloperidol-induced Fos expression in the striatum, nucleus accumbens and lateral septal nucleus. At a dose that reduced the cataleptic effect of haloperidol, scopolamine decreased the neuroleptic-induced Fos expression in the striatum and lateral septal nucleus but not the nucleus accumbens. These results indicate that haloperidol may increase c-fos expression in medium spiny striatal neurons indirectly by enhancing striatal acetylcholine release. They are also consistent with the hypothesis that neuroleptic-induced increases in striatal c-fos expression are predictive of extrapyramidal side effects produced by these compounds.


Induction of fos expression by activity in the spinal rhythm generator for scratching.

Fos expression was evaluated immunohistochemically in L7-S1 spinal segments after inducing fictive scratching in paralysed, unanaesthetized, decerebrate cats. The activity was induced by cutaneous stimulation of the pinna on one side and recorded from peripheral nerves. A cumulative duration of scratching of 60 to 90 min was effective in inducing fos expression. Most Fos-positive neurones were found in the dorsolateral part of the ventral horn and in the intermediate region of the spinal cord on the scratching side. In sham-operated animals the finding of Fos-positive neurones in these areas was very rare.


Differential effects of ibogaine pretreatment on brain levels of morphine and (+)-amphetamine.

Previous studies in rats have shown that ibogaine inhibits neurochemical and behavioral effects of morphine yet potentiates similar effects of (+)-amphetamine. To assess whether these different functional interactions have a metabolic basis, brain levels of morphine and (+)-amphetamine were measured by gas chromatography-mass spectrometry after ibogaine pretreatment (19 h before injection of morphine or (+)-amphetamine). Ibogaine pretreatment had no effect on brain morphine levels, either at 30 min or 2 h after morphine injection; however, ibogaine significantly increased brain amphetamine levels at 30 min and, to a greater extent, at 2 h after (+)-amphetamine injection. These and other data suggest that ibogaine irreversibly inhibits an amphetamine-metabolizing enzyme. The functional interactions between ibogaine and (+)-amphetamine, but not those between ibogaine and morphine, may result from a hepatic drug-drug interaction.


Sick photoreceptors attract activated microglia from the ganglion cell layer: a model to study the inflammatory cascades in rats with inherited retinal dystrophy.

Understanding of neuron-glial interactions in neurodegenerative diseases remains limited, but is of crucial importance for unravelling the etiology of such disorders both in humans and in animals. The present work employed a new, function-dependent technique for examining the role of microglia in rats afflicted with inherited retinal photoreceptor degeneration (strain: royal college of surgeons, RCS). In this rat strain, which served as a surrogate for human inherited retinal photoreceptor dystrophy, the optic nerve was cut and the ganglion cells were retrogradely labelled with the fluorescent dye 4Di-10ASP. The experiment was performed under three different conditions: (1) at the 50th day of postnatal age (P50) when there is ongoing degeneration of photoreceptor cells, (2) at P110 when most photoreceptors were degenerated and (3) at P50 in non-dystrophic rats of the Sprague-Dawley strain. After axotomy-induced ganglion cell death and labelling of activated microglia by phagocytosis of the ganglion cell debris, this study monitored whether the labelled and therefore identifiable microglial cells within the severed ganglion cell layer (GCL) are prompted to migrate and to participate in phagocytosis of debris produced within the endogenously degenerating photoreceptor cell layer (PRL). Massive migration of microglial cells from the GCL to the PRL occurred in dystrophic animals with optic nerve transection at P50. Double-labelling of microglial cells with the fluorescent dye ingested within the GCL and with lipofuscin ingested within the PRL indicated the ability of these cells to perform double-phagocytosis.(ABSTRACT TRUNCATED AT 250 WORDS)


Expression of c-fos protein by immunohistochemically identified oxytocin neurons in the rat hypothalamus upon osmotic stimulation.

Double immunostaining for c-fos and oxytocin (OXY) was used to study the topography and time course of the metabolic activation of the hypothalamic oxytocinergic system upon osmotic stress in the male rat. Animals injected i.p. with hypertonic saline expressed c-fos-like immunoreactivity (FLI) in the paraventricular (PVN), periventricular (PEV) and supraoptic (SON) hypothalamic nuclei, and in the preoptic and retrochiasmatic regions, as early as 30 min after stimulation and up to 6 h, while these areas were mostly devoid of staining in isotonic saline-injected animals. The activation of the oxytocinergic system peaked at 30 min and declined at different rates in the PVN and in the SON after 90 min. The maximal percentage of OXY neurons expressing FLI upon osmotic stress was about 80% in the SON, PEV and LSN, 60% in the PVN and 50% in the medial preoptic area. Activated OXY neurons were found in both the magnocellular and parvocellular divisions of the system. These data show that OXY nuclei in the rat hypothalamus are differentially activated by osmotic stress. They also suggest a role of OXY in the central as well as in the humoral response to changes in plasma osmolarity.


Electrophysiological actions of acetate, a metabolite of ethanol, on hippocampal dentate granule neurons: interactions with adenosine.

Acetate is the primary breakdown product of ethanol metabolism in the liver and has been found in the brain following ethanol ingestion in rats. Systemically administered acetate has been shown to cause motor impairment, an effect which is blocked by the adenosine receptor blocker, 8-phenyltheophylline (8-PT). The effects of sodium acetate were investigated in this study using intracellular recording techniques in rat hippocampal dentate granule cells, and were compared to the actions of ethanol and adenosine individually and in conjunction with 8-PT. Acetate hyperpolarized the membrane at 0.4-0.8 mM. The amplitude and duration of the postspike train afterhyperpolarization (AHP) were increased by acetate when the cell was repolarized to the control resting membrane potential. Comparable results were seen in voltage clamp. Acetate also decreased spike frequency adaptation. The effects of acetate were mimicked by adenosine (50 microM) and ethanol (20 mM). The ethanol effects occluded those produced by acetate. All of the effects of acetate, adenosine and ethanol could be inhibited with prior perfusion of 8-PT (1-10 microM). These data suggest that the actions of the major metabolite of ethanol, acetate, may be mediated by adenosine receptor activation.


Arginine vasopressin mobilises intracellular calcium via V1-receptor activation in astrocytes (pituicytes) cultured from adult rat neural lobes.

An extremely close association exists between the membranes of the neurosecretory endings and the resident astrocytes (pituicytes) of the neurohypophysis. Indeed, synaptoid contacts involving neurosecretory vesicle-containing axons contacting pituicytes have been observed, suggesting pituicytes as targets of the products released from neurosecretory axons. We have investigated the effects of various neural lobe peptides on pituicytes in primary culture from adult neurohypophyses. Using Fura-2 loaded cells and dynamic ratio imaging, we have determined that arginine vasopressin (AVP) or V1- but not V2-receptor agonists, mobilise pituicyte intracellular Ca2+ ([Ca2+]i) in the absence of extracellular Ca2+. AVP was consistently effective at concentrations of 10 nM or higher in elevating [Ca2+]i by 200-1000 nM. These responses could be blocked by V1-antagonists and were shown to be associated with accumulation of phosphoinositides. Oxytocin was also found to mobilise [Ca2+]i but was effective only at higher concentrations than for AVP. Oxytocin-evoked [Ca2+]i elevations were also blocked by V1-antagonists. Raising [K+]0 was ineffective in changing [Ca2+]i suggesting that these cells lack voltage-gated Ca2+ channels. We conclude that pituicytes possess V1-receptors, activation of which mobilises [Ca2+]i, possibly functioning to initiate a Ca(2+)-activated K+ conductance which could contribute to further depolarisation of secretory terminals and facilitate exocytosis.


Alterations in behavior, steroid hormones and natural killer cell activity in male transgenic TGF alpha mice.

The expression of transforming growth factor alpha (TGF alpha) is widely distributed throughout many normal and neoplastic tissues, but its physiological significance remains unclear. We have utilized male transgenic mice overexpressing the gene encoding human TGF alpha in multiple tissues to further identify those functions which are influenced by this protein. Male TGF alpha mice develop hepatocellular carcinoma at the age of 10-15 months. At the age of 2-3 months these mice, compared to age matched CD-1 controls, spent significantly longer times immobile in Porsolt's swim test, a model of stress and depressive behavior, and exhibiting aggressive behavior in the resident-intruder test. In contrast, the transgenic TGF alpha mice did not differ from the controls in either the plusmaze test of anxiety, or in their voluntary alcohol intake. Significantly, the TGF alpha mice exhibited a 25% lower Natural Killer (NK) cell activity and a four-fold increase in the plasma levels of 17-beta-estradiol (E2) than the controls. No significant changes in plasma testosterone or corticosterone levels were noted. The results indicate that transgenic male mice overexpressing TGF alpha exhibit behaviors characteristic of both an impaired ability to cope with stress and an increased aggressivity. The TGF alpha mice also show reduced NK cell activity and increased plasma estradiol concentrations. The present data suggest that TGF alpha may be important in influencing behavioral, immunological and hormonal systems prior to the onset of tumors. It remains to be determined whether hepatocarcinoma is associated with the direct proliferative and transforming effects of TGF alpha and/or indirect effects mediated through immune, hormonal and behavioral mechanisms.


Electrical stimulation of the paraventricular nucleus attenuates pyrogen fever in the rabbit.

Arginine vasopressin (AVP) perfused within the ventral septal area (VSA) suppresses fever normally evoked by pyrogenic substances, including Salmonella abortus equi (SAE). Neurons containing AVP and located within the paraventricular nucleus (PVN) or the nearby bed nucleus of the stria terminalis (BnST) are believed to have projections to this septal region. A series of experiments was undertaken to determine whether electrical stimulation of these areas, which might be expected to cause the release of AVP within the VSA, would affect similarly the pathogenesis of fever. A stainless steel cannula was implanted surgically in each of 22 male New Zealand White rabbits and a monopolar electrode was lowered through this guide cannula to the PVN or BnST areas. Electrical stimulation (20 Hz, 10 s on, 10 s off, 2.6-3.2 V) was initiated 30 min prior to and was continued until 90 min after the intravenous (i.v.) administration of 0.1-1.0 micrograms of SAE (1.0 ml carrier vehicle). While afebrile body temperature remained unchanged, electrical stimulation of sites located in the rostral extension of the PVN effectively attenuated the pyrogen-induced fever. Stimulation of sites outside these areas did not affect either the absolute magnitude or the duration of the fever. Although the reduction in fever was most pronounced during the period of electrical stimulation, in some cases the fever remained suppressed beyond the application of the current. These experiments provide the first evidence that electrical stimulation of paraventricular areas with AVP-containing cell bodies is effective in suppressing a fever evoked by systemic administration of a pyrogen. Although untested, it is possible that a stimulus-induced release of AVP within the VSA is responsible for the attenuation of the fever.


Angiotensinogen is secreted by pure rat neuronal cell cultures.

Previous studies are divided between those which support a neuroglial (astrocyte) source for brain angiotensinogen and those which indicate that both astrocytes and neurones synthesize the precursor of angiotensin II. In this study, separate cultures of astrocytes and neuronal cells were prepared and established as being essentially pure by appropriate immunocytochemical cell markers. Angiotensinogen production by these cultures, as measured by a direct radioimmunoassay, was 20.74 +/- 3.62 ng angiotensinogen/10(6) cells/24 h (mean +/- S.D., n = 8) for astrocytes and 4.39 +/- 0.94 ng/10(6) cells/24 h (mean +/- S.D., n = 29) for neurones. Angiotensinogen secretion from both cell types was unaffected by treatments which stimulate the regulatory secretory pathway by modulating intracellular cAMP levels. In contrast, it was reduced from 23.20 +/- 2.14 to 8.14 +/- 1.31 ng/10(6) cells/24 h (S.E.M., n = 7) in astrocyte cultures by the constitutive pathway inhibitor, monensin. Angiotensinogen secreted by astrocytes and neurones was compared to pure angiotensinogen and that in plasma and cerebrospinal fluid (CSF) by cation-exchange mono S column chromatography. Pure angiotensinogen eluted as two separate peaks corresponding to the major forms of plasma angiotensinogen, whereas angiotensinogen in CSF and culture media coeluted with a third minor form of plasma angiotensinogen. It was concluded that neuronal cells as well as astrocytes secrete angiotensinogen which is distinctly different from plasma angiotensinogen.


Antagonism of cocaine's pharmacological effects by the stimulant dopaminergic antagonists, (+)-AJ76 and (+)-UH232.

The aminotetralins (+)-AJ76 and (+)-UH232 are stimulant dopaminergic antagonists, which may preferentially antagonize autoreceptors of dopamine nerve terminals. Both agents antagonized cocaine's depressant effects on firing rates of ventral tegmental dopaminergic neurons, but (+)-UH232 was much more potent. When injected simultaneously with cocaine, (+)-UH232 inhibited and (+)-AJ76 enhanced the locomotor stimulation observed during the first 30 min following s.c. cocaine administration. However, (+)-AJ76 antagonized cocaine-induced stereotypies as well as the later more intense cocaine locomotor stimulation. It is suggested that preferential dopamine autoreceptor antagonists may provide a novel approach to a pharmacotherapy for treating cocaine abuse.


Effects of 5-HT receptor antagonists on seizure susceptibility and locomotor activity in DBA/2 mice.

The effect of antagonists of serotonin (5-HT) receptor subtypes and alpha 2-adrenoceptors was investigated on audiogenic seizures and locomotor activity in DBA/2 mice. 5HT1c receptor antagonists (mianserin and cyproheptadine), 5-HT3 receptor antagonist (zacopride) and 5-HT4 receptor antagonist (ICS 205-930) increased the latency of audiogenic seizures and decreased the severity of convulsions in young (20-27 days old) DBA/2 mice. However, the effect of these antagonists varied in older (30-37 days old) mice. Ketanserin, 5-HT2 receptor antagonist, was devoid of any activity on audiogenic seizures. Yohimbine (0.5 mg/kg, i.p.), an alpha 2-adrenoceptor antagonist, increased the severity of audiogenic seizures, and the anti-convulsant effect of 5-HT receptor subtypes antagonists became more pronounced in the presence of yohimbine. 5-HT3 and 5-HT4 receptor antagonists produced hypolocomotor activity in young mice whereas 5-HT1c and 5-HT2 receptor antagonists were devoid of any effect on locomotor activity. Yohimbine did not induce any effect on locomotor activity but the mice exhibited more pronounced hypolocomotor activity following the administration of 5-HT3, 5-HT4 and 5HT1c receptor antagonists in the presence of yohimbine. However, the results varied with these agents in the older mice. These observations implicate a role of 5-HT1c, 5-HT3, 5-HT4 and alpha 2-adrenoceptors in audiogenic seizures in young DBA/2 mice, and 5-HT3 and 5-HT4 receptors in locomotor activity in these mice. Furthermore, these results also suggest an interaction between 5-HT receptors and alpha 2-adrenoceptors, and differential development patterns of various 5-HT receptor subtypes in the CNS.


Ceruletide, a CCK-like peptide, attenuates dopamine release from the rat striatum via a central site of action.

Ceruletide (CLT), a cholecystokinin-like peptide was given subcutaneously or via the perfusate to rats to clarify the site of action (peripheral vs. central location) of CLT, using in vivo microdialysis techniques. Striatal dopamine (DA) release induced by haloperidol (HPD) was significantly inhibited by subcutaneously administered CLT (160 micrograms/kg) when given with a perfusate containing 15 mM K+. Subdiaphragmatic vagotomies failed to block the inhibitory effect of CLT. CLT (10(-15)-10(-11) M) locally applied, via a dialysis tube, produced an inhibitory effect on HPD-induced DA release in the striatum in a dose-dependent manner. The inhibitory effect of CLT given subcutaneously on DA release was antagonized by both locally applied proglumide and systemically administered L-365,260. These findings suggest that systemically administered CLT can directly act on the striatal neurons via CCK-B receptors and produce an inhibitory effect on DA release in the striatum under appropriate depolarization.


[3H]MK-801 binding to the NMDA receptor complex, and its modulation in human frontal cortex during development and aging.

[3H]MK-801 binding was found to decline with age in well washed membranes from human frontal cortex taken from an age series from 24 weeks gestation to 100 years old. The decline was significant under basal conditions (no added modulators) (P less than 0.01), and highly significant under stimulation with glutamate, glycine and spermidine alone and in combination (P less than 0.001). Scatchard analysis in the presence of glutamate and glycine showed this decline was due to a loss in the number of [3H]MK-801 binding sites rather than a change in the affinity of the binding site. There was a highly significant age related reduction in the attenuation of [3H]MK-801 binding by zinc (P less than 0.001). In foetal and neonatal cases up to 7 weeks of age spermidine behaved in an antagonistic manner, inhibiting rather than stimulating [3H]MK-801 binding, when alone or in the presence of glutamate and glycine. The changes in influence of glutamate, glycine, spermidine and zinc on [3H]MK-801 binding during development and aging were not due to other pre- or postmortem factors. The reverse effect of spermidine in the foetal and neonatal cases has therapeutic implications in the treatment of neonates with antiischaemic agents whose action involves the polyamine site.


Regional distribution of copper, zinc and iron in the brain in Long-Evans Cinnamon (LEC) rats with a new mutation causing hereditary hepatitis.

In Long-Evans Cinnamon (LEC) rats of three different ages (7, 13 and 32 weeks old) concentrations of Cu, Zn and Fe were measured in 8 regions of the brain. The LEC groups aged 7 and 13 weeks showed low concentrations of Cu in all regions compared to Long-Evans Agouti (LEA) rats. In 32-week-old LEC rats, however, Cu concentrations increased in 7 regions, in particular, significantly so in the striatum, hypothalamus, cerebellum, midbrain and cortex. Changes of Zn concentration were not found in any region. The Fe concentration increased in cortex and olfactory lobes. The three LEC groups showed a very high concentration of hepatic Cu and a low concentration of serum Cu compared to LEA rats. In LEC rats aged 32 weeks, however, hepatic Cu decreased and serum Cu increased compared to the other two LEC groups. These results suggest that the increase of the cerebral Cu concentration is closely related to the inherently abnormal Cu metabolism and then to the changes of Cu metabolism from about 13 weeks after birth.


Appearance of interleukin-1 in macrophages and in ramified microglia in the brain of endotoxin-treated rats: a pathway for the induction of non-specific symptoms of sickness?

The presence and cellular localization of interleukin-1 beta immunoreactivity (irIL-1) in and around the brain was investigated using immunocytochemistry on Bouin's fixed vibratome brain sections of control and endotoxin-treated rats. Peripheral administration of endotoxin resulted in the appearance of irIL-1 in cells in the meninges, choroid plexus, brain blood vessels and in non-neuronal cells in the brain parenchyma. Using monoclonal and polyclonal antibodies to macrophage and astrocyte antigens, the endotoxin-induced irIL-1 positive cells could be identified as macrophages in the meninges and choroid plexus (ED2), perivascular cells (ED2) and ramified microglial cells (GSA-I-B4 isolectin). Our data demonstrate a pathway for the induction of non-specific sickness symptoms in response to endotoxin.


Capillary NMDA receptors regulate blood-brain barrier function and breakdown.

Polyamines and their regulatory synthetic enzyme ornithine decarboxylase (ODC) have been implicated in blood-brain barrier (BBB) breakdown following cryogenic injury. ODC activation and BBB breakdown are prevented by MK-801, indicating involvement of NMDA receptors. Studies in isolated rat cerebral capillaries supports the presence of NMDA receptors linked to ODC. NMDA (1-50 microM) stimulated capillary uptake of horseradish peroxidase, 2-deoxy-[14C]glucose, and 45 Ca in a receptor-, concentration-, polyamine- and Ca(2+)-dependent manner. We suggest that NMDA receptors may couple capillary transport of nutrients to glutamate-mediated neuronal excitation, and when overestimated disrupt normal BBB function.


Sexually dimorphic concentrations of arginine vasotocin in sensory regions of the amphibian brain.

Arginine vasotocin (AVT) regulates reproductive behaviors in amphibians. We measured AVT in the brains of bullfrogs (Rana catesbeiana) and newts (Taricha granulosa) using radioimmunoassay. In bullfrogs, AVT concentrations were greater in males, compared to females, in the amygdala pars lateralis, optic tectum, and tegmentum. Concentrations in the dorsolateral nucleus were greater in females. In newts, AVT concentrations were also greater in the tectum and tegmentum of males. AVT may modulate dimorphic behaviors by acting at these sites.


The morphology of GABA-immunoreactive neurons in the accessory olfactory bulb of rats.

GABA-immunoreactive (IR) neurons were observed in the accessory olfactory bulb (AOB) of adult female rats. Many somata and dendritic trees of periglomerular-located cells were GABA-IR and the size of their somata was variable. Numerous somata and dendrites in the granule cell layer were IR. These results suggest that a large number of the interneurons in the AOB are GABA-IR.


Effect of angiotensin II and atrial natriuretic factor on neurons in the subfornical organ of ducks and rats in vitro.

Atrial natriuretic factor (ANF) antagonizes many angiotensin II (ANGII)-induced effects on osmoregulatory relevant parameters in vivo. In this study ANF analogues decreased the spontaneous and the ANGII-induced electrical activity of subfornical organ (SFO) neurons in rats, but had no effect on ANGII sensitive or insensitive SFO neurons in ducks. These results suggest a more distinct functional separation for the responsiveness to ANGII and ANF in birds compared to mammals.


In vivo kindling does not alter afterhyperpolarizations (AHPs) following action potential firing in vitro in basolateral amygdala neurons.

Kindling in vivo results in enhanced glutamatergic synaptic transmission and epileptiform bursting in vitro in neurons of the basolateral amygdala (BLA). We tested the hypothesis that reduction of intrinsic inhibitory mechanisms, such as the slow- and medium-afterhyperpolarizations (s-AHPs, m-AHPs), contributes to the enhanced neuronal excitability observed in kindling-induced epileptogenesis using intracellular recording methodology. In these studies, neurons were recorded from the BLA contralateral to the kindling site. AHPs following depolarizing current-induced (100 ms, 1 nA) action potentials were recorded from BLA neurons of control and kindled animals. We found no difference in the amplitude of the s-AHP and m-AHP, or the duration of the s-AHP between control and kindled neurons. In addition, kindling did not alter the distribution of accommodating/non-accommodating BLA neurons (as assessed from neuronal responses during long (500 ms) depolarizing current injection). It is concluded that an alteration in the neuronal network within the BLA rather than a blockade of an intrinsic inhibitory mechanism underlies the enhanced excitability recorded in BLA neurons following kindling.


Stress induces atrophy of apical dendrites of hippocampal CA3 pyramidal neurons.

The hippocampus is vulnerable to the damaging actions of insults such as transient ischemia and repetitive stimulation, as well as repeated exposure to exogenous glucocorticoids. This study investigated effects of a repeated psychological stressor, restraint, on the CA3 pyramidal neurons which are vulnerable to damage by repetitive stimulation. Repeated daily restraint stress for 21 days caused apical dendrites of CA3 pyramidal neurons to atrophy, while basal CA3 dendrites did not change. Rats undergoing this treatment were healthy and showed some adaptation of the glucocorticoid stress response over 21 days; however, stress reduced body weight gain by 14% and increased adrenal weight relative to body weight by 20%. Results are discussed in relation to the possible role of adrenal steroids and excitatory amino acids.


The effect of cycloheximide on natural and X-ray-induced cell death in the developing cerebral cortex.

Naturally occurring cell death in the cerebral cortex and subcortical white matter is increased after X-irradiation, and this process is curbed with cycloheximide, an inhibitor of protein synthesis. However, cycloheximide alone increases cell death during development, and this effect is dose-dependent. This suggests that, in both normal and experimentally-induced cortical cell death during development, different proteins are activated or inhibited, depending on the agent, the time of its application, and the previous metabolic or functional state of the cell.


Brain implants in man do not break down the blood-brain barrier to dopamine and domperidone.

We have evaluated the blood-brain barrier (BBB) in 8 Parkinsonian patients before and after stereotactic implantation of foetal mesencephalon (STIM) and one patient with an adrenal medullary implant. Parenteral administration of dopamine did not reverse Parkinsonism pre-operatively or at 5 days, 1, 2, 3, 4 months and 1 year post-operatively. Apomorphine and domperidone reversed Parkinsonism and produced dyskinesia in all patients pre- and post-operatively. We conclude that the BBB remains intact to dopamine following implantation.


A topographic representation of auditory space in the external nucleus of the inferior colliculus of the guinea-pig.

The possibility that the external nucleus of the inferior colliculus (ICX) of the pigmented guinea-pig contains a map of auditory space has been investigated. Auditory stimuli consisted of broad-band sound delivered under free-field anechoic conditions from a range of positions around the animal's azimuthal axis. The responses of clusters of neurons in the ICX to threshold and to near-threshold stimuli displayed sharp spatial tuning. The responses recorded from rostral ICX revealed a preference for auditory stimuli in the anterior field while more caudal neurons preferentially responded to sounds presented in the posterior field. Neurons at intermediate points, along the rostro-caudal axis of the nucleus, displayed preferences for sound stimuli in appropriately intermediate field positions along the contralateral azimuthal axis. At higher stimulus intensities the spatial tuning of the responses decreased, but the optimal direction of preference was usually retained. The contribution of binaural processing to auditory spatial tuning was evident, since unilateral cochlea ablation destroyed the spatial tuning at higher stimulus intensities. The results presented provide the first evidence that a topographically ordered representation of the contralateral auditory azimuth is present in the ICX of a mammal.


A calcium-stimulated serine protease from monkey brain degrades the beta-amyloid precursor protein.

Amyloid deposition, a histopathological feature of Alzheimer's disease brain, may be the underlying cause of this disease. The isolation of enzymes involved in both the normal and aberrant or alternative processing of the beta-amyloid precursor protein may lead to an understanding of how beta-protein, the major component of amyloid deposits, is formed in the brain parenchyma and vasculature of Alzheimer's disease patients and aged humans. As the same kind of deposits is also found in aged primates, the use of primates will undoubtedly help to understand the mechanisms of amyloid deposition, both spatially and temporally. Here we report the partial purification from adult monkey brain of a calcium-activated serine protease that is immunoreactive with antibodies against cathepsin G and is potentially involved in the abnormal degradation of the beta-amyloid precursor protein. Moreover, immunoreactivity with cathepsin G antibodies was localised to astrocytes in both adult and aged monkey cortex, suggesting that our protease may be expressed in astrocytes.


Effect of orbital enucleation on glucose homeostasis and morphology of the suprachiasmatic nucleus.

In rats there is a direct neural connection called the retinohypothalamic tract (RHT) from retinal ganglion cells to the ventrolateral part of the suprachiasmatic nucleus (SCN), which has neurons containing vasoactive intestinal polypeptide (VIP)-like substance. Previously, we observed that bilateral orbital enucleation (blinding) caused temporary suppression of the hyperglycemic response to intracranial injection of 2-deoxy-D-glucose (2DG) from week 4 to 6 after blinding. Moreover, bilateral lesions of the SCN had a similar effect. From these findings, we supposed that the neurons responsible for the hyperglycemic response to 2DG were present in the SCN, that after blinding these neurons temporarily lost their activity, and that this functional change was reflected in the morphology of the SCN. To investigate this possibility, we examined the morphological changes of the SCN by Nissl staining and immunohistochemical studies with anti-VIP and anti-peptide histidine isoleucine (PHI) antibodies in blinded rats, and the relationship between these morphological changes and the hyperglycemic response to 2DG. After surgical blinding, we observed following changes. (1) The optic chiasm became thinner. (2) The SCN became displaced rostrally. (3) The density of neurons in the middle to caudal part of the SCN, where the retinal ganglion cells projected, decreased markedly without change in cell number during the period when the hyperglycemic response to intracranial injection of 2DG was temporarily suppressed after blinding. The first and second changes seemed to reflect reduction of fibers and axon terminals of retinal ganglion cells and their innervation, respectively. As the third change was parallel with suppression of the hyperglycemic response to 2DG injection, it may reflect functional change of the neurons in the SCN that are responsible for the hyperglycemia due to 2DG.


Sleep homeostasis in suprachiasmatic nuclei-lesioned rats: effects of sleep deprivation and triazolam administration.

The electroencephalogram (EEG) and electromyogram of rats with lesions in the suprachiasmatic nuclei (SCNx) were recorded during two series of 24-h baseline, 6-h sleep deprivation (SD), and 24-h recovery. At recovery onset, rats were injected i.p. with vehicle (VEH) control solution or 0.4 mg/kg triazolam (TRZ) in a balanced crossover design. Consecutive 10-s epochs were scored for vigilance states and EEG power spectra were computed. Arousal states were uniformly distributed during 24-h baseline (wake 47% of recording time, non-rapid-eye movement sleep (nonREMS) 47%, REMS 7%), and EEG spectra (0-25 Hz) were devoid of significant trends. State-specific EEG power spectra profiles in SCNx rats were similar to those of intact animals reported previously. However, EEG delta power (0.5-3.5 Hz) of nonREMS was markedly lower in SCNx rats. Recovery from 6-h SD was characterised by a short-lasting reduction of REMS, and a long-lasting increase of nonREMS time at the cost of wakefulness. EEG delta power rebounded during the first 8 h in recovery, and fell below baseline level after 12 h in recovery. During 0-2 h TRZ recovery, rats spent more time in nonREMS with higher EEG slow wave activity as compared to the corresponding VEH recovery period. EEG slow wave activity fell below baseline levels 10 h after TRZ injection and termination of SD. We conclude that major features of homeostatic sleep EEG regulation are present in SCNx rats.(ABSTRACT TRUNCATED AT 250 WORDS)


Early post-natal administration of 5,7-dihydroxytryptamine destroys 5-HT neurons but does not affect spatial memory.

The neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) may play an important role in learning and memory. It has also been suggested that 5-HT abnormalities may mediate some aspects of the cognitive disorders associated with Korsakoff syndrome and Alzheimer's Disease. The effect of intracisternally applied 5-HT neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT) on learning and memory in rodents was evaluated. Three-day-old rat pups were treated with pargyline (40 mg/kg, i.p.) followed by 5,7-DHT (50 micrograms/pup) and returned to the dam for a month. At 75 days of age, rats were tested on a learning set problem in the Morris water maze for 5 days followed by 30 days of testing in a 12-arm radial maze with 8 of the 12 arms baited. In the Morris water maze, the latency to locate the hidden platform did not differ significantly for 5,7-DHT treated and control rats (F less than 1.0). Similarly, 5,7-DHT treated rats performed comparably to controls on the 12-arm radial maze (F less than 1.0). At 106 days of age the assay of tryptophan hydroxylase activity in the dorsal raphe nuclei and hippocampus showed marked reduction (86%, 78%, respectively) in 5,7-DHT treated animals compared to vehicle injected controls. Immunocytochemical analysis was consistent with the biochemical results. In 5,7-DHT treated animals there was severe loss of neurons that bind 5-HT antibody in the dorsal and medial raphe nuclei.(ABSTRACT TRUNCATED AT 250 WORDS)


Role of the cell recognition molecule, cognin, in GABAergic differentiation in chick retina.

Previous work showed that GABAergic differentiation in developing chick retina depends on insulin and cell interactions. Here, we investigated whether it depended on cell signaling mediated by retina cognin, a 50 kDa cell recognition molecule. Cognin mediates cell adhesion in vitro and occurs on retinal neurons that become both GABAergic and cholinergic. We investigated two markers of GABAergic differentiation: glutamate decarboxylase (GAD) activity and high-affinity GABA uptake. Both increase during differentiation of retinal neurons in culture and can be easily measured. We blocked cognin-mediated cell signaling with cognin antibody and found a reduction of the developmental increase in GAD activity in cultures of retinal neurons from 7 and 11 day chick embryos. There was no reduction of high-affinity GABA uptake. This suggested that cognin-mediated signaling was necessary for the normal developmental increase in GAD but not for high-affinity GABA uptake. These results contrasted with our previous observations on cholinergic differentiation in cultured retinal neurons. We found that cognin antibody blocked the normal developmental increase in choline acetyltransferase (ChAT) only if the cells were exposed before embryonic day 7. Thus, while both GAD and ChAT activity appear to be controlled by cell signaling involving cognin, the periods of developmental sensitivity for the two differentiation markers are different. Antibodies to other adhesion molecules, Ng-CAM, and N-cadherin, did not similarly affect GAD activity. Antibodies to laminin at a 10-fold higher concentration inhibited GAD activity only in early embryonic retina. Tests for protein synthesis and "housekeeping" enzyme activity demonstrated that the cognin antibody effect was selective for neuronal differentiation pathways.(ABSTRACT TRUNCATED AT 250 WORDS)


Interregional correlations of resting cerebral glucose metabolism in old and young women.

A correlational analysis of normalized (regional to whole-brain) regional cerebral metabolic rates for glucose obtained in the 'resting' state (eyes covered, ears plugged) using [18F]fluorodeoxyglucose, demonstrated differences between old and young women in patterns of functional associations. Fifteen healthy young (age less than 40 years) and 17 healthy old women (age greater than 64 years) were scanned with a Scanditronix PC1024-7B tomograph. The brain was divided into 65 regions of interest. The old women had fewer and less positive correlations between pairs of metabolic ratios in the frontal and parietal cortices. The results suggest an age-related reduction in frontal and parietal functional interactions in the 'resting' state that is consistent with a prior correlation analysis using a low resolution ECAT II scanner on young and old men. Reduced functional interactions may reflect age-related cognitive changes.


Differential inhibition of acetylcholinesterase molecular forms in normal and Alzheimer disease brain.

Molecular forms of acetylcholinesterase were studied in three brain regions from Alzheimer disease patients and non-demented, age-matched controls. In Alzheimer disease patients, the membrane-bound G4 form was decreased in frontal (-71%) and parietal cortex (-45%) and in the caudate-putamen (-47%) from control levels. We also found a decrease of aqueous-soluble acetylcholinesterase molecular forms in the aqueous-soluble acetylcholinesterase molecular forms in the caudate-putamen region. The effect of three clinically significant acetylcholinesterase inhibitors, heptyl-physostigmine, physostigmine and edrophonium, on aqueous-soluble acetylcholinesterase molecular forms of the caudate-putamen was investigated. Heptyl-physostigmine, a physostigmine analogue, showed preferential inhibition for the G1 form. On the contrary, edrophonium inhibited the G4 form more potently than the G1 form. Physostigmine inhibited both forms with similar potency. The clinical implications of selective acetylcholinesterase inhibitors are discussed.


Aromatase activity in cultured brain cells: difference between neurons and glia.

At the level of the central nervous system (CNS) of several mammalian and non-mammalian species, estrogens may be intracellularly formed from circulating androgens through the action of the aromatase complex. Estrogenic steroids play a crucial role in organizing and directing certain behavioral and neuroendocrine responses both during the fetal/neonatal life and in adulthood. Biochemical and immunocytochemical studies have shown that the aromatase is particularly concentrated in CNS areas involved in the control of reproductive functions, such as the hypothalamus, the preoptic area and the limbic system; despite this large body of evidence, the exact cellular localization of this enzymatic complex within the different cell populations of the brain is still uncertain. In the experiments described here, the presence of the aromatase has been evaluated in the two main cellular components of the brain: the neurons and the glia. In these experiments, cultures of neurons obtained from the brains of 14-15-day-old rat embryos, mixed glial cells from 1-day-old rats and type 1 astrocytes derived from cultured glial cells, have been utilized. The aromatase has been also evaluated in oligodendrocytes isolated from adult male rat brain by density gradient ultracentrifugation. The aromatase activity has been assayed by an 'in vitro' radiometric method which quantifies the production of tritiated water from [1 beta-3H]-androstenedione as an index of estrogen formation. The validity of the method has been verified both on the placental microsomes and on rat hypothalamic tissue, in which the actual formation of estrogens has also been measured.(ABSTRACT TRUNCATED AT 250 WORDS)


Basal forebrain cholinergic neurons in aged rat brain are more susceptible to ibotenate-induced degeneration than neurons in young adult brain.

Choline acetyltransferase (ChAT) activity, acetylcholinesterase (AChE) activity, and [3H]nicotine binding site density were measured in neocortex from unoperated (control) and nucleus basalis (NB)-lesioned young (2-3 months old) and aged (23-24 months old) rats. In control animals, neither enzyme activities nor the density of nicotine binding sites were altered as a function of age. However, age-related differences were apparent 2 weeks following unilateral infusions of ibotenic acid into the right NB. NB lesion-induced decreases in enzyme activities were significantly greater in ipsilateral neocortices from aged rats; ChAT and AChE activities in young animals decreased by 59 and 53%, respectively, while both enzyme activities in aged rats decreased by 72%. NB lesions decreased significantly the density of nicotine binding sites in ipsilateral neocortices from both young and aged rats; binding decreased by 23-26% in young rats and by 31-34% in aged animals. Results indicate that the basal forebrain cholinergic system in the aged rat is more susceptible to ibotenate-induced degeneration than neurons in young animals.


Enhancement of REM sleep with auditory stimulation in young and old rats.

Auditory stimulation applied during rapid eye movement (REM) sleep enhances the duration of REM sleep in cats and humans. The present experiment investigated whether auditory stimulation would enhance REM sleep in young (3-6 months) rats, and also in old (22-24 months) rats which have impaired REM sleep. Baseline sleep records were obtained on two days. Sleep patterns were then assessed during auditory stimulation test sessions. In young rats, auditory stimulation was administered during each REM sleep bout. In old rats, auditory stimulation was administered on a fixed schedule (10 min of stimulation alternating with 15 min quiet). The day after the stimulation session, an additional sleep record (Day 2) was obtained for each rat. In young rats, auditory stimulation enhanced both REM sleep duration and total REM sleep time. In the old rats, which showed impaired sleep measures as compared to young animals, auditory stimulation enhanced both total REM sleep time and the number of REM sleep periods. Residual proactive effects of auditory stimulation (Day 2) were observed in both young and old rats. Thus, auditory stimulation is an effective manipulation with which to augment REM sleep in both young and old rats, and partially attenuates REM sleep impairments in old rats.


The evidence for astrocytes as a target for central noradrenergic activity: expression of adrenergic receptors.

Our recognition and understanding of adrenergic receptor expression by astrocytes and their cultured counterparts, astroglia, has occurred primarily over the past 2 decades. The advances in our knowledge have come about largely through the advent of new techniques with which to study neurotransmitter receptors, coupled with improvements in our ability to isolate, purify, and identify this central nervous system (CNS) cell type. The development of pharmacological tools such as second messenger assays, iodinated ligands, autoradiography, and intracellular electrophysiological recordings, paralleled that of cultured clonal cells lines of glial origin, purified astroglial primary cultures, isolations of astrocytes from adult tissues, and immunocytochemical staining for the astrocyte-specific glial fibrillary acidic protein (GFAP). As these techniques were combined and applied to the study of astrocyte pharmacology, our understanding of adrenergic receptor expression by these cells deepened. This review is an account of how these events have shaped our understanding of astrocytic adrenergic receptor expression.


Resting and reactive astrocytes express adrenergic receptors in the adult rat brain.

Adrenergic receptor subtypes were localized in situ and in cells isolated from the trigeminal motor nucleus and several other brain regions. To study receptor expression in reactive astrocytes, motor neuron degeneration and a glial reaction were induced in the trigeminal motor nucleus by the injection of the toxic lectin Ricin communis into the trigeminal motor root. Autoradiography following incubation of tissue sections in the alpha 1-ligand 125IBE 2254 (HEAT) or the beta-ligand 125Iodocyanopindolol (ICYP) showed a decrease in alpha 1- and an increase in beta-adrenergic receptor binding in the region of neuronal degeneration and gliosis. Glial hypertrophy, rather than hyperplasia, appears to be mainly responsible for the increased beta-binding, since inhibition of mitosis with cytosine arabinofuranoside only partially blocked elevations of beta-adrenergic receptor binding and GFAP immunolabelling in reactive astrocytes. More direct evidence for the expression of adrenergic receptors in normal and reactive astrocytes was obtained by combined autoradiography and immunohistochemistry of cells dissociated from the cerebral cortex, striatum, cerebellum, and trigeminal motor nucleus of adult rats. More than 88% of GFAP-positive astrocytes showed varying densities of beta-adrenergic receptor binding. In each region, the beta 2-subtype was proportionally greater than the beta 1-subtype. Astrocytes also expressed a significant density of alpha 1-receptors. Trigeminal motor neurons did not show beta-receptor binding, but had a density of alpha 1-receptors tenfold greater than astrocytes. A model for the role of astrocytes in adrenergic receptor-mediated modulation of trigeminal motor neuron excitability is discussed.


Autonomic control of neuronal-astrocytic interactions, regulating metabolic activities, and ion fluxes in the CNS.

It is generally assumed that the brain, in contrast to all other organs, is not equipped with an autonomic nervous system, regulating blood supply, and cellular activities. This may be because systemic administration of most drugs acting on monoaminergic or cholinergic receptors have little or no effect on cerebral blood flow and metabolism. However, intrathecal administration of noradrenaline does, indeed, influence both blood flow and energy metabolism in the brain. The present review focuses on effects of noradrenaline or serotonin on energy metabolism, turnover of amino acid transmitters and ion homeostasis, with special emphasis on the cellular localization. Noradrenergic agonists stimulate brain metabolism in vivo as well as many aspects of energy metabolism, Na+,K(+)-ATPase activity and uptake of transmitter amino acids in astrocytes in primary cultures, with little or no effect on corresponding preparations of neurons. Serotonin acts differently, decreasing potassium-induced release of glutamate from both neurons and astrocytes. Little is known about the effects of acetylcholine. The functional significance of these effects is discussed.


Alteration of neuronal responses in the subthalamic nucleus following globus pallidus and neostriatal lesions in rats.

Kainic acid (2-4 days) or ibotenic acid (7-9 days) lesions of the globus pallidus or neostriatum altered the responsiveness of subthalamic nucleus neurons to electrical stimulation of the agranular frontal cortex. Three changes in responsiveness were seen following pallidal lesion: a) An increase in the proportion of responding cells as compared to controls (approximately 90% vs. 60%); b) an increase in the total duration of the evoked response (62.5 ms vs. 28.6 ms); 3) an increase in magnitude of response (9.76 spikes per stimulus vs. 3.24). Both an increase in firing rate (17.94 spikes/s vs. 8.23) and a change to a bursty spontaneous firing pattern were seen. Lesion of the neostriatum had fewer but opposite effects including decreased firing rate (7.21 spikes/s) and decreased total response duration (18.9 ms). These results suggest that the normal tonic inhibition of the subthalamic nucleus by the globus pallidus may play an important role in controlling subthalamic neuronal spontaneous activity and responsiveness. The neostriatum may influence the subthalamic nucleus via the globus pallidus. Globus pallidus lesions may have important consequences on the specificity of cortical control of the subthalamic nucleus and may alter subthalamic influence on basal ganglia output.


GABA levels and GAD immunoreactivity in the deep cerebellar nuclei of rats with altered olivo-cerebellar function.

Immunocytochemistry was used to examine the distribution, size, and density of glutamic acid decarboxylase immunoreactive (GAD+) puncta in two animal models with movement disorders, the genetically dystonic (dt) rat and rats with 3-acetylpyridine (3AP) lesions of the inferior olive. In both models, GAD activity is increased in the deep cerebellar nuclei (DCN) where the enzyme is localized primarily in the terminals of Purkinje cells. GABA levels were also measured in the DCN. The general distribution of GAD+ puncta in the DCN was similar in all groups. Immediately after the 3AP lesions, however, GABA levels were elevated in 3AP rats in comparison with both normal rats and age-matched dt rats. GAD+ puncta were also larger than normal in the 3AP group at this time, although the magnitude of this effect declined over a 2-week recovery period. Puncta density was decreased in the medial nucleus only in 25-day-old dt rats in comparisons with normal littermates. These findings are discussed in the context of previously reported differences in the firing rate of Purkinje cells in dt and 3AP-treated rats.


Place and taste aversion learning: role of basal forebrain, parietal cortex, and amygdala.

Animals with nucleus basalis magnocellularis (NBM), parietal cortex, dorsolateral frontal cortex, amygdala or control lesions were tested in a neophobia and taste aversion learning task. Only animals with basolateral amygdala lesions were impaired in taste aversion learning and in displaying neophobia to a novel flavor. This finding suggested a dissociation between the function of the NBM component of the basal forebrain cholinergic system and the amygdala. The same animals with NBM or control lesions were then tested for acquisition of a spatial navigation task using a dry-land version (cheese board) of the Morris water maze. Animals with NBM lesions were impaired in this task relative to control animals. Animals with parietal cortex lesions displayed a comparable deficit in the place navigation task. These findings suggest parallel functions for the NBM component of the basal forebrain system and the parietal cortex. The role of the NBM in mediating memory appears to be limited in that it does not play a role in all learning situations.


Quantitative trait loci associated with brain weight in the BXD/Ty recombinant inbred mouse strains.

Adult C57BL/6J (B6) male mice had 37% heavier brains than did DBA/2J (D2) mice, while their body weights did not differ. The BXD recombinant inbred (RI) series of 20 strains, derived from a cross between B6 and D2 inbred strains, was used as the initial screen to determine significant associations between male brain weight and brain:body weight ratio, with allelic variation at 360 known marker gene loci. For brain weight, this yielded five candidate chromosome regions, each reflecting a possible quantitative trait locus (QTL) site affecting brain weight. The second step was to test as many of these five as possible using standard (non-RI) inbred strain data for brain weight previously reported in the literature. For this purpose, only strains possessing the same alleles as the B6 or D2 strains were used. Sufficient data to test two of the five candidate QTL were available. Of these, one was strongly supported as a site affecting brain weight--the D7rp2 region of chromosome 7. For the brain to body weight ratio, four chromosome regions emerged as significantly associated in the BXD series, but none were amenable to testing due to a lack of allelic information for the standard inbred strains. However, two of these regions showed highly significant associations (p less than 0.001, single test) that merit consideration as QTL sites for future testing. These two are the Hba region on chromosome 11 and the D17Tu7 region on chromosome 17. The genetic correlation between brain and body weight was low (r = 0.28), indicating that these two traits are largely genetically independent in the BXD RI series.


A reexamination of the effects of intracerebroventricular glucocorticoids in adrenalectomized rats.

Several investigators have reported that many of the behavioral and metabolic effects of ADX can be reversed by appropriate levels of glucocorticoids administered either peripherally or centrally. The present studies were conducted to offer a comparison of the effects of orally administered corticosterone (CORT) with ICV glucocorticoids [CORT, CORT acetate, or dexamethasone (DEX)]. Of particular interest were the effects of glucocorticoid treatment on body weight gain and on macronutrient self-selection. Adult male Sprague-Dawley rats were fitted with ICV cannulae and either bilaterally ADX or given sham operations. In the first experiment, ADX animals were initially treated systematically with CORT (20 micrograms/ml in their drinking water). After a wash-out period during which no steroids were administered, ADX rats were given daily ICV CORT injections (100 micrograms/day in 10 microliters). Systemic CORT treatment promotes weight gain and normal food choice patterns in ADX rats. ICV injections failed to promote weight gain in ADX rats, and daily injection of the vehicle promoted a weight loss in sham-operated controls. Four additional experiments were conducted. ADX, glucocorticoid-treated animals and ADX, vehicle-treated controls as well as sham-operated, vehicle-treated controls were used to assess the effects of both steroid and vehicle on body weight gain and dietary selection patterns. ADX ICV-glucocorticoid-treated animals typically failed to gain weight at the rate observed when ADX rats are treated with CORT systematically. Under one condition, ADX-CORT-treated animals gained weight at a rate comparable to untreated controls, but their ICV-injected control group failed to gain weight.(ABSTRACT TRUNCATED AT 250 WORDS)


Hypothalamic lesions increase neuronal immunoreactivity for neuropeptide Y.

An enhanced production of hypothalamic neuropeptide Y (NPY) now appears to underlie a number of hyperphagia syndromes. However, the role of NPY in the hyperphagia induced by hypothalamic lesions has not yet been explored. Here, hypothalamic lesions were induced in mice by administration of goldthioglucose (GTG) and brain sections were stained immunocytochemically for NPY without pretreatment with colchicine. NPY-immunoreactive somas were visible in the hypothalamus of only one of eight control mice but were identified in the hypothalami of six of seven mice with GTG lesions. This suggests that GTG lesions cause an enhanced production of NPY, perhaps due to interruption of fibers from arcuate dopaminergic neurons that normally inhibit NPY+ cells. Thus, hypothalamic lesions may provoke hyperphagia by stimulating the production of NPY.


Alterations in hippocampal cholinergic receptors and hippocampal behaviors after early exposure to nicotine.

Mice were exposed to nicotine prenatally by injecting the mother with 1.5 mg/kg nicotine SC twice daily on gestation days 9-18 (PreN mice) or neonatally by daily SC injections of 1.5 mg/kg nicotine on postnatal days 2-21 (NeoN mice). At age 50 days, hippocampal muscarinic receptors Bmax of PreN and NeoN mice were 58% and 79% above control, respectively (p less than 0.01); Kd was unaffected by early nicotine exposure. Eight-arm maze performance of nicotine-exposed animals fell behind control level. Both PreN and NeoN made approximately 10% less correct responses in the first eight trials than controls throughout the test period (p less than 0.01). By the last day of testing, PreN needed 23% and NeoN 31% more trials than controls to enter all arms (p less than 0.001). In addition, PreN needed 35 and NeoN 42% more days than controls to reach criterion (p less than 0.05). Similarly, while 61% of controls reached criterion by day 6 only 17% of PreN and 25% of NeoN reached criterion (p less than 0.01). In the Morris maze, PreN needed from 43-119% more time to reach the platform (p less than 0.001). In the spatial probe test, PreN animals made 35% fewer crosses over the area of the missing platform (p less than 0.001). The study suggests that nicotine administered to the fetus or neonate alters septohippocampal chemistry and induces deficits in hippocampus-related behaviors. The possible reversal of the behavioral changes by manipulating the cholinergic innervations should be the subject of future investigations.


Behavioral consequences in animal tests of anxiety and exploration of exposure to cat odor.

Rats exposed to a cloth impregnated with cat odor showed a decreased number of contacts with the cloth and time in contact with it and increased time sheltering from it. Exposure to the odor of rat blood produced similar, though less marked, changes and also increased the number of occasions the rat sought shelter. Exposure to the odor of disinfectant changed only the time in contact with the cloth. Exposure to cat odor also resulted in anxiogenic responses in the social interaction and elevated plus-maze tests that could be detected up to 1 h, but not 24 h, after odor exposure. Decreased exploration in the holeboard could also be detected up to 1 h, but not 24 h, after exposure to cat odor. The time in contact with the cloth, the incidence of, and time spent sheltering did not decrease over five successive exposures to the odor of a cat. The number of contacts with the control odor cloth increased over successive exposures, but contacts with the cat odor cloth did not change over successive exposures. The decreased exploration in the holeboard, as a result of prior exposure to cat odor, showed rapid habituation, as did the anxiogenic response detected in the social interaction test, whereas that detected in the plus-maze persisted for up to five odor exposures.


Overlapping visual fields and ipsilateral retinal projections in turtles.

The possible relationship between overlap of the visual fields and the importance of ipsilateral retinal projections was investigated in the two Chelonian genera Chinemys and Trionyx. Of these two species, Trionyx has more frontally located eyes, yet ipsilateral retinal projections could not be demonstrated by radioautography. In Chinemys, on the other hand, the ipsilateral retinothalamic projections are extensive. It is suggested that, in contrast to Trionyx, the anatomic substrate of stereoscopic vision in Chinemys may be similar to that in mammals.


Cerebellar norepinephrine infusions facilitate recovery after sensorimotor cortex injury.

This study reports the effects of norepinephrine infusions into cerebellum after unilateral sensorimotor cortex injury. The results demonstrate an immediate and permanent acceleration in motor recovery in awake rats infused with 150 micrograms norepinephrine into the cerebellum contralateral to a right sensorimotor cortex ablation. A vehicle infusion or infusion of norepinephrine into the ipsilateral cerebellum produced no beneficial effects on functional recovery.


Effect of nonpeptide angiotensin receptor antagonists on water intake and salt appetite in rats.

Nonpeptide angiotensin AT-1 and AT-2 receptor antagonists were administered cerebroventricularly to rats and their effects on various types of angiotensin II (AII)-stimulated water and NaCl intakes examined. The AT-1 receptor blocker, losartan potassium (DUP 753), inhibited water intake evoked by central administration of AII, with the 50% inhibitory dose being less than 0.1 microgram. The functional inhibition by higher doses lasted at least 1 h. The AT-2 receptor antagonist PD 123319 also inhibited AII-induced water intake, but at doses about tenfold higher than losartan. Central, but not peripheral, administration of losartan partially inhibited NaCl intake induced by either sodium depletion, treatment with angiotensin converting enzyme inhibitors (CEIs), or adrenalectomy. PD 123319 partially inhibited NaCl intake induced by both sodium depletion and administration of CEI, but not after adrenalectomy. Another AT-2 receptor antagonist, CGP 42112A, likewise inhibited NaCl intake after sodium deprivation. These data suggest that both AT-1 and AT-2 receptor subtypes in the brain are involved in angiotensin-related water and NaCl intakes.


Kainic acid-induced seizures in aged rats: neurochemical correlates.

This study was conducted to assess the functional integrity of the kainate receptor-mediated seizure response in aged rats. Kainic acid was administered systemically to aged female Long-Evans (LE) rats and aged male F344 rats and the proconvulsant actions of kainic acid was compared to adult controls. The effects of kainic acid on brain regional content of monoamines and amino acids was also determined in the aged female LE and adult control rats. The latency to full clonic-tonic seizures was significantly reduced in aged female LE rats, and the number of seizures was significantly increased above that of the controls. There was increased mortality and a reduction in the latency to exhibit wet dog shakes in the aged F344 rats. Studies were also conducted to evaluate the role of ovarian hormones, route of administration, and dose of kainic acid in mediating the enhanced proconvulsant actions of kainic acid in aged rats. The neurochemical studies suggested that kainic acid significantly enhanced the release of ASP, GLU, and norepinephrine (NE) in the aged rats exhibiting clonic-tonic seizures. The adult rats given the same dose of kainic acid (15 mg/kg, IP) did not exhibit any significant change in brain content of monoamines or amino acids except for a reduction in mediobasal hypothalamic NE. An in vitro study was also conducted using brain slices from adult and aged F344 and it was found that aged rats released significantly more ASP than adults in response to kainic acid. These neurochemical findings were discussed in relation to previous studies of age-related alterations in excitatory amino acids (EAAs) and the role of EAA and NE in modulating limbic seizures. This study has clearly demonstrated that aged rats may be more susceptible to the excitotoxic action of EEAs acting through kainetic receptors.


Artificial rearing alters development of the nucleus of the solitary tract.

Previous studies have shown that damage induced to fungiform papillae of the anterior tongue at postnatal day 2 (P2) alters both pre- and postsynaptic development of gustatory recipient zones within the rostral nucleus of the solitary tract (NST). The present study was conducted to determine whether or not artificial rearing (AR) manipulations, which reduce normal orochemical stimulation during early postnatal development, would be sufficient to produce alterations in anatomical development of the rostral gustatory NST. Two groups of Long-Evans hooded rats were examined. One group received normal rearing with a lactating dam from birth to weaning (mother reared; MR). A second group of animals received artificial rearing via intragastric cannulae between the ages of P4 and P14, and were thereafter returned to lactating dams until the age of weaning (P21). Following weaning and maturation to adulthood (P49), the organization of gustatory afferent terminal fields in the NST was examined using fluorescent tracing procedures which permit the simultaneous visualization of gustatory afferent terminal fields arising from the seventh and ninth cranial nerves. Results show that AR manipulations between the ages of P4 and P14 produce alterations in development of gustatory afferent terminal fields in the NST that are essentially similar to those observed following early postnatal receptor damage. These results confirm previous suggestions that orochemical stimulation during a limited portion of rats' postnatal life is essential in inducing normal presynaptic development in the gustatory NST.


Ultrastructure of cholinergic neurons in the laterodorsal tegmental nucleus of the rat: interaction with catecholamine fibers.

The ultrastructure of choline acetyltransferase (ChAT)-immunoreactive neurons in the laterodorsal tegmental nucleus (TLD) of the rat was investigated by immunohistochemical techniques. The immunoreactive neurons were medium to large in size, with a few elongated dendrites, contained well-developed cytoplasm, and a nucleus with deep infoldings. They received many nonimmunoreactive, mostly asymmetric synaptic inputs on their soma and dendrites. ChAT-immunoreactive, usually myelinated, axons were occasionally seen in TLD. Only one immunoreactive axon terminal was observed within TLD, and it made synaptic contact with a nonimmunoreactive neuronal perikaryon. The synaptic interactions between ChAT-immunoreactive neurons and tyrosine hydroxylase (TH)-immunoreactive fibers in the TLD were investigated with a double immunohistochemical staining method. ChAT-immunoreactivity detected with a beta-galactosidase method was light blue-green in the light microscope and formed dot-like electron dense particles at the electron microscopic level. TH-immunoreactivity, visualized with a nickel-enhanced immunoperoxidase method, was dark blue-black in the light microscope and diffusely opaque in the electron microscope. Therefore, the difference between these two kinds of immunoreactivity could be quite easily distinguished at both light and electron microscopic levels. In the light microscope, TH-positive fibers were often closely apposed to ChAT-immunoreactive cell bodies and dendrites in TLD. In the electron microscope, the cell soma and proximal dendrites of ChAT-immunoreactive neurons received synaptic contacts from TH-immunoreactive axon terminals. These results provide a morphological basis for catecholaminergic regulation of the cholinergic reticular system.


A computer-assisted direct-imaging system to obtain numerical densities of neurons in human cortex.

Studies of the numerical density of microscopic items in brain tissue is a time-consuming endeavor. However, such information is important for numerous issues such as the relationship between structure and function in the normal brain, individual differences, and studies of brains of neuropsychiatric patients. A computer-assisted imaging system specifically devised to obtain estimates of numerical densities in human cortex is described here. Its main advantage is that the microscopist can analyze the original image directly under the microscope, and most aspects of data acquisition and quantitative analysis are accomplished by the computer. The key features of the system are a Microvid (an electronic camera lucida) and the use of X, Y, and Z stage encoders in conjunction with three-dimensional computer software. The complete system is relatively inexpensive and is simple to set up and use. The reliability and validity of the numerical densities obtained using this system are documented.


[Plasma cholesterol levels and ischemic heart disease: new findings and new approaches].

The information explosion characteristic of recent years has presented a series of findings enabling a more effective prevention of ischemic heart disease by controlling low density lipoprotein (LDL) levels of cholesterol. The detection of LDL receptors has provided new information on the mechanisms regulating the level of plasma LDL. Data on competitive inhibitors of endogenous cholesterol synthesis have afforded new possibilities of pharmacological control of LDL levels. Studies of primary prevention of ischemic heart disease have yielded evidence showing that a 1% decrease of cholesterol level reduces coronary risk by 2%. A prospective study of the relationship between cholesterol levels and coronary mortality, absolutely unique as to its extent (368,000 middle-aged men followed up over a period of 6 years) has demonstrated that there is no borderline cholesterol level below which coronary risk would be absolutely excluded. Between total cholesterol level and coronary mortality there is a close, continual and graded relationship. In light of these findings, total cholesterol levels have been reclassified: desirable levels -5.2 x 10(-3) mol.l-1, borderline risk levels under 5.2-6.2 x 10(-3) mol.l-1, and high risk levels--above 6.2 x 10(-3) mol.l-1. In subjects with several risk factors (smoking, hypertension, familial occurrence of heart, heart disease, obesity, diabetes mellitus, HDL cholesterol below 0.9 x 10(-3) mol.l-1) the level of total cholesterol should be brought down below 4 x 10(-3) mol.l-1.(ABSTRACT TRUNCATED AT 250 WORDS)


[Rapid prenatal diagnosis of cystic fibrosis using the polymerase chain reaction: results of the first 5 cases].

Cystic fibrosis (CF) is an autosomal recessive lethal disease with an incidence in Slovakia of 1 affected in 1800 newborns. Within a year the incidence amounts to about 50 cases. Though the responsible gene has already been cloned, the only effective approach to prevention is prenatal diagnosis in the first and second trimester of pregnancy. The paper presents the results of the first five cases of prenatal diagnosis of CF established by the new rapid method of DNA analysis, polymerase chain reaction (PCR). Delta F508 deletion mutation and closely linked DNA polymorphism KM19/PstI were assessed. In two of the five cases studied the fetuses were found to be affected and pregnancy termination was indicated. To exclude the possibility of fetal DNA contamination with maternal DNA, the hypervariable DNA polymorphism VNTR apoB was determined simultaneously. The advantages of this approach are demonstrated on cases of prenatal diagnosis performed in two families where contamination of fetal DNA could be excluded. The value of the PCR method is being compared with that of Southern's hybridization method. (Tab. 2, Fig. 4, Ref. 27.).


[The effect of cyclophosphamide and methotrexate on gastric emptying and secretion in rats].

The effect of cyclophosphamide and methotrexate was studied in rats on the evacuation of 50% BaSO4 suspension from the stomach (doses: 50-200 mg.kg-1 and 5-20 mg.kg-1 s.c.) and on HCl secretion (doses: 100 mg.kg-1 and 10 mg.kg-1 s.c.) after stimulation with pentagastrin (25 micrograms.kg-1 s.c.). Both cytostatics were found to slow down gastric evacuation and to suppress the effect of pentagastrin on gastric secretion. The presented changes may relate to the adverse effects on the GIT observed in patients treated with the given cytostatics. (Fig. 4, Ref. 17.)


Thermally evoked tail avoidance reflex: input-output relationships and their modulation.

Latency to onset and magnitude (angular displacement) of thermally evoked tail avoidance reflexes (TETAR) to graded thermal stimuli were measured in pentobarbital-treated and untreated rats. The latency to onset was inversely and the magnitude was directly proportional to the thermal stimulus intensity. Pentobarbital prolonged the latency to onset of the TETAR to low by not high stimulus intensities. Activation of (-)-nicotine sensitive brainstem hyperalgesic processes shortened the latency and increased the magnitude of the TETAR. The hyperalgesic actions of (-)-nicotine were most demonstrable at lower thermal stimulus intensities. These studies suggest that the TETAR is graded in intensity as the stimulus intensity is increased and that the response evoked by different intensities of stimulus probably involve common neurophysiologic mechanisms.


[Incidental detection of coronary artery anomalies].

A retrospective study is presented analyzing the clinical findings in 15 patients in the age range of 18-58 years (12 men, 3 women) with anomalous origin of the coronary arteries diagnosed from 5500 coronary arteriograms performed in the authors' institute IKEM. In 4 patients the anomaly was isolated, in 11 patients associated, and that in 6 with coronary disease, in 3 with rheumatic disease, and in 2 patients with atrial septal defect. Although the disease is congenital, its manifestations appeared only in the 16th to 54th year of life, presenting a nonspecific clinical picture, physical, ECG and XR findings. Changes in the ergometric test and left ventriculography were determined by the associated disease. Diagnosis of the anomaly was established by selective coronarography.


Responses of lateral hypothalamic neurons recorded in vitro to moderate changes in glucose concentration.

Single unit neuronal activity of lateral hypothalamic neurons was recorded extracellularly in hypothalamic slices. Glucose concentration in the perfusate was modified in small amounts to simulate normal physiological glycemic fluctuations associated with feeding. Several neurons responded reliably under these conditions. These data on simulated small glycemic changes, based on observations in the whole animal, suggest that the modulation of neuronal activity reported in this study is a result of a direct action of glucose on cells in this region of the hypothalamus.


Do callosal projection neurons reflect sex differences in axon number?

We have reported that female rats have more axons in the splenium of the corpus callosum than do male rats (12). To determine if the greater number of axons found in female rats might be reflected in a larger distribution of callosal projection neurons, horseradish peroxidase (HRP) was injected into the visual cortex of 55-65-day-old rats of both sexes that had been housed in a complex environment since weaning. The pattern of labeled neurons was examined in tangential sections in the cortex contralateral to the injection site, and three-dimensional reconstructions were quantified at the area 17/18a border and in area 18b. Male and female rats were found to have indistinguishable distributions of labeled callosal projection neurons. The present study failed to find an obvious difference in the distribution of projection neurons as the basis for the sex differences in axon number, but because of the limitations of tracing techniques, subtle differences cannot be excluded.


Epileptogenic activity in the amygdala is not affected by the amidine steroid, R 5135.

The synthetic steroid amidine 3-alpha-hydroxy-16-imino-5-beta-17aza androstan-11-one (R 5135) is known to elicit long-lasting spiking in the cortex in the presence of neocortical damage. R 5135 administered to amygdaloid-kindled and naive rats resulted in regular, high-amplitude spiking in the cortex but only occasionally elicited small-amplitude spikes in the amygdala (AMY) and hippocampus (HPC). Interictal spikes from the AMY of kindled rats were not synchronized with cortical spikes induced by the steroid. Given that R 5135 is known to be a GABAA receptor antagonist, these findings suggest that GABAA receptors in AMY and HPC may have lower affinity for 3 alpha-hydroxysteroids.


[Professor Antonín Spilka in the history of the Comenius University Medical School in Bratislava].

Professor MUDr. Antonín Spilka was one of the outstanding personalities of the Medical Faculty of Comenius University in Bratislava in the first years of its existence. He was among the first Czech medical doctors who came to Bratislava and was among the last ones to leave it. In 1919 he was substantially involved in the establishment of the Institute of Morbid Anatomy and he was its Head till 1926. In the period from 1927 to 1938 he was Head of the Institute of Medical History, Philosophy, and Hodogetics. Prof. Spilka was first Deputy Dean then he became Dean of the Faculty and over many years he was actively engaged and held various academic positions in different faculty and university institutions. Stricken by a severe disease in 1926, he nevertheless remained active focusing his interest on history of medicine and health care and end medical ethics.


Changes in levels of thyroid hormones and TSH in acute myocardial infarction.

The changes in levels of total serum thyroxine (T4), total serum triiodothyronine (T3), effective thyroxine ratio (ETR), and serum TSH were investigated in 88 patients with acute myocardial infarction (AMI). The T4 and T3 values decreased significantly on the third day of hospitalization to return to starting values on the 7th day. ETR values were significantly reduced on the 3rd day and remained so also on the 7th day. Compared to starting values, serum TSH levels were increased on the 7th day of hospitalization, yet not significantly. In the group of 16 patients who died within 96 hours, ETR values were significantly increased on the 1st day of hospitalization (immediately after admission) in comparison with the group of AMI surviving patients. The highest frequency rate of abnormally low T3 values was found in patients who died within 96 hours. With respect to thyroid function evaluation, ETR proved to be the most satisfactory parameter with the lowest percentage of abnormal values.


[Bacterial resistance to aminoglycoside antibiotics].

Aminoglycoside antibiotics, such as gentamicin, netilmicin, tobramycin, amikacin, may be inactivated by resistant bacteria producing three types of enzymes: O-nucleotidyltransferases, O-phosphotransferases and N-acetyltransferases. Mechanisms of aminoglycoside resistance were analyzed in clinical isolates of gram-negative bacteria from several regions of Czecho-Slovakia and compared with the use of aminoglycosides. Production of acetyltransferases (AAC) and nucleotidyltransferases (ANT) was observed in 84% of bacterial isolates. The majority of bacterial strains studied produced the AAC/3/enzyme (62%). Due to dissemination of plasmids coding for the AAC/3/enzyme, the majority of Czecho-Slovak gentamicin-resistant strains was also tobramycin resistant (93%) and netilmicin resistant (68%). Amikacin remains the most effective aminoglycoside antibiotic against multiresistant bacterial strains.


Determination of free calcium.

A computer program designed to be user friendly is described in this report. Two types of calculations are provided: a) determination of free calcium concentration based on known total salt concentration and b) those which calculate total salt concentration required to insure a desired free calcium concentration in the buffered system. The user can choose up to 10 different ligands, nine different cations (known total concentration) and 10 concentrations (either free or total) of the variable cation (e.g. calcium) per calculation. Thus, this program does not restrict its user to one or two parameters (e.g., buffer and/or ions). Data generated using this method are in excellent agreement with those derived using programs in current use.


[The role of mitochondrial energy metabolism and oxygen free radicals in the pathogenesis of experimental autoimmune myocarditis].

In a model of autoimmune myocarditis in guinea piga, the authors studied energy producing processes in mitochondria and the role of oxygen free radical generation in tissue injury. A significant decrease in the capacity of oxidative phosphorylation was detected in parameters QO2 (S3) on the basis of glutamate + malate (p < 0.005) and pyruvate (p < 0.05) measurements. Other parameters studied were however only insignificantly reduced in myocarditic heart mitochondria as compared to controls. The activity of mitochondrial cytochrome oxidase was also insignificantly reduced in animals with myocarditis. Generation of oxygen free radicals was in the presence of the inflammatory infiltrate in this model not significantly higher than in the intact myocardial tissue.


[Prophylactic administration of selected antibiotics in hospitals in the Slovak Republic].

Over a period of ten years prophylactic administration of selected antibiotics was evaluated three times (in 1973, 1983, and in 1988) in the same ten hospitals of the Slovak Republic. The study was focused on the use of gentamicin (GEN), cotrimoxasol (COT) and cephalosporins (CEP). Prophylactic administration of antibiotics was found to be increasing. GEN is being given less frequently, while CEP are administered more often, which is considered to be a positive trend. The period of prophylactic administration of antibiotics is still inadequately long with an average of 10.7 days. Evaluation of antibiotic administration showed that antibacterial substances have the highest rate of prophylactic administration in patients with oncologic diseases, followed by patients with diseases of the urinogenital system. A positive development was recorded in the perinatal period with a decreasing trend in the prophylactic administration of antibiotics.


[Is there a relation between cardiorespiratory fitness and systolic time intervals?].

Systolic time intervals measured by polycardiography significantly correlated with some spiroergometric parameters of cardiorespiratory fitness both at rest and during dynamic exercise. The correlations were mostly free. There were considerable intraindividual differences. The method of polycardiography can thus not be recommended for exact intraindividual differentiation of left vetricular functional ability. Intraindividual detection of systolic time intervals will be the subject of our further investigation.


Some solvents for antiepileptics have proepileptic potencies in the WAG/Rij rat model for absence epilepsy.

Some solvents for antiepileptics were tested, for 4 consecutive days, in a rat model (the WAG/Rij inbred strain) for absence epilepsy. Electroencephalogram registrations and behavioral observations suggested that both Tween-80 and a mixture of saline/ethanol/propylene glycol caused an increase in the number of epileptic phenomena. This increase was not significant and restricted to injection day 1 with Tween-80 but was significantly present during all 4 injection days with the saline/ethanol/propylene glycol mixture. Furthermore, with this latter solvent the increase became larger during consecutive days. Because of the proepileptic potencies and the differential time effects of these solvents, their usage should be seriously questioned.


[Surgical treatment of supravalvular aortic stenosis].

Over the last 22 years, two children were operated on for supraventricular aortic stenosis at the Institute of Cardiovascular Diseases in Bratislava. Both cases presented a localized form of supravalvular aortic stenosis. Simple elipsoid flaps were used without extended aortoplasty. One of the two children, a 12-year-old boy with Williams' syndrome died of endocarditis in the early postoperative period. In the 10-year-old girl with familial supravalvular aortic stenosis the operation was successful, although the defect was combined with supravalvular muscular obstruction. The authors emphasize the possibility of choice between two surgical procedures according to the localization of the stenosis with respect to the valvular apparatus.


Calcium entry blocker ameliorates ischemic neuronal damage in monkey hippocampus.

Effects of treatment with (+/-)-1-(3,4-dimethoxyphenyl)-2-(4- diphenylmethylpiperazinyl)ethanol dihydrochloride (NC-1100), a calcium entry blocker, on ischemic neuronal damage were investigated. Monkeys were subjected to temporary occlusion of eight (bilateral common carotid, internal and external carotid, and vertebral arteries) major arteries. Blood flow was restored after 5, 10, 13, and 15 min occlusion, and NC-1100 (1 mg/kg) was then immediately infused intravenously. Monkeys were killed by perfusion fixation 5 days after occlusion. All brain regions were then histologically investigated for ischemic neuronal changes. Physiological data of NC-1100-treated subjects were not significantly different than those of untreated subjects. Heart rate tended to decrease after ischemia in treated subjects. Occlusion of 8 arteries for 10 to 15 min produced ischemic neuronal damage confined exclusively to the CA1 subfield of the hippocampus. Treatment with NC-1100 markedly reduced ischemic neuronal damage in the CA1 subfield of the hippocampus. It is suggested that postischemic treatment with the calcium entry blocker, NC-1100, might protect the brain from the ischemic damage produced in patients suffering from transient ischemia.


[The effect of streptozotocin diabetes on lipid levels in the myocardium in young rats].

The effect of intraperitoneally administered streptozotocin was studied in 8-, 10-, and 12-week-old rats. The total triacylglycerol content was found to be significantly increased in all the three groups studied, and that by 59.64% in the 8-week old group, by 54.86% in the 10-week-old group, and by 50.57% in the 12-week-old group. The level of total phospholipids increased only in the 8-week-old group of diabetic animals, and that by 11.09%, whereas in the other age groups studied it remained unchanged. In the level of individual phospholipids changes occurred in 8-week-old rats, namely phosphatidylcholine increased by 53.0% and sphingomyelin by 23.8%. In 10- and 12-week-old diabetic rats the only change was recorded in the level of cardiolipin which increased by 54.23% in 12-week-old animals.


[The activities of Professor Alojz Chura at the Comenius University Medical School in Bratislava].

One of the most outstanding personalities of Slovak nationality acting at the Medical Faculty of Comenius University in the first two decades of its existence was Prof. MUDr. Alojz Chura. He was among the first students of the Faculty and was then its active member until 1945. The aim of the present study was to contribute to a better understanding and unbiased evaluation of the importance and impact of the activities of this remarkable personality of Slovak pediatrics. In 1925 MUDr. Chura started to work at the Teaching Hospital of Pediatrics and in 1945 he was forced to leave both his position of Director of the Hospital and that of Full Professor of Pediatrics. As Director he had succeeded Prof. Brdlík who on leaving for Prague had suggested Prof. Chura for this responsible position. The contribution of Prof. Chura to the development of pediatrics in Slovakia was exceptional. His extensive sociological study "Slovakia without the Young Generation" laid the basis of social pediatrics in Slovakia. The Teaching Hospital of Pediatrics experienced considerable development under his guidance and that in all its areas of activity, i.e. teaching, prevention, therapy, and research. Besides his manifold activities at the Hospital and Medical Faculty, Prof. Chura was involved in many pursuits, particularly those which were related to the car of the youngest generation. He was Chairman of the Association of Pediatricians in Slovakia for many years. The study analyzes also the Memorandum issued in 1935 which is an important document of the actual social and health conditions in the Slovak country.(ABSTRACT TRUNCATED AT 250 WORDS)


[Relation between lipid-bound sialic acid in blood serum and plasma andin human tumors].

Athymic mice with transplanted osteosarcoma and carcinoma of the rectum were found to have increased blood plasma levels of lipid-bound sialic acid (LSA). To verify the applicability of the method of LSA determination, patients with cancer of the mammary gland, rectum, and colon were examined for their LSA level. The serum LSA level was significantly increased in patients with cancer of the mammary gland and rectum, compared to levels determined in the serum of healthy volunteers. The serum LSA level elevation was even more pronounced in patients with carcinoma of the colon. In patients with carcinoma of the colon who were in remission at the time of blood collection the serum LSA level was found to be reduced to control values.


[The effect of extrarenal factors on certain functions of the kidney and urinary tract. A radionuclide study].

The authors present their experiences concerning the effect of extrarenal factors on the results of radionuclide examination. Functional and functional-morphological examinations of the kidneys and urinary tract can be negatively affected particularly by emotional stress, orthostasis, dehydration, increased kidney motility, address administered drugs during examination (diuretics), drug treatment of the primary disease, muscular strain, cold, pain, increased pressure in the vicinity of the kidney, hypertension, hypotension, as well as further conditions. Radionuclide methods can objectify these processes, the given negative effects can however be presumed to occur also at other examination procedures of the kidney and urinary tract. The conditions of examinations have thus to be optimized and standardized. The examining physician has to know which drugs the patient is receiving and he has to know their effect on renal function.