The participation of the parafascicular thalamic nucleus and of the neostriatal cholinoreactive system in regulating the food-procuring reflex in rats at different stages of learning]

Effects of bilateral lesions of the thalamic parafascicular nucleus (Pf) and bilateral microinjections of scopolamine (cholinolytic) and carbacholine (cholinomimetic) into rat neostriatum on the strength of pressing the bar at different stages of acquisition of food-procuring reflex were studied in 51 rats. At the stage of training of food-procuring movements (only strong bar pressings were reinforced) without introduction of a conditioned stimulus, the Pf lesions decreased the rate of learning and increased the number of week pressings. At this stage, scopolamine neostriatal microinjections against the background of the Pf lesions increased the number of strong and did not affect the number of week bar pressings. On the contrary, carbacholine decreased the number of strong and increased the number of week pressings in comparison with the preinjection background. In the trained group of rats, at the stage of reflex restoration (strong bar pressings were reinforced only during the action of a conditioned stimulus) after the Pf destruction, the reflex restoration time depended on the level of presurgery training. Striatal scopolamine injections that primarily after surgery led to a high level of correct reflex realization induced a sharp impairment in reflex performance on a microinjection day, and carbacholine microinjections against the background of low reflex performance did not change this level after surgery.     

Effect of thymalin on protein synthesis in the brain and conditioned-reflex activity of the progeny of neurosensitized female rats

Thymalin administration to two-week-old offspring of neurosensitized female rats prevented the development of protein synthesis disturbances in the central nervous system and the retention of conditioned reflex of passive avoidance. Thymalin injection to the offspring of intact female rats improved conditioned reflex retention and did not affect brain protein synthesis. A possible mechanism of thymalin effect in conditions of congenital neuroimmunopathology is discussed.     

Effect of cadmium chloride on the processes of learning and memory in rats

Intraperitoneal injection of cadmium chloride (4 mg/kg) to rats before elaboration or reproduction of two-way avoidance conditioned reflex (TACR) disturbs both these processes. Deterioration of elaboration does not affect connections fixation and their subsequent reproduction. Injection of the substance before the elaboration of passive avoidance conditioned reflex (PACR) depresses elaboration and consolidation. Injection of cadmium chloride before testing of PACR preservation does not influence the processes of engrams reproduction. The observed disturbances cannot be connected with changes of animals motor activity.     

Immunocytochemical localization of S-100 beta beta protein in olfactory and supporting cells of lamb olfactory epithelium

By immunocytochemistry, we have identified two novel cell types, olfactory and supporting cells of lamb olfactory epithelium, expressing S-100 beta beta protein. S-100 immune reaction product was observed on ciliary and plasma membranes, on axonemes and in the cytoplasm adjacent to plasma membranes and to basal bodies of olfactory vesicles. A brief treatment of olfactory mucosae with Triton X-100 before fixation is necessary for detection of S-100 beta beta protein within olfactory vesicles. In the absence of such a treatment, the immune reaction product is restricted to ciliary and plasma membranes. On the other hand, irrespective of pre-treatment of olfactory mucosae, S-100 beta immune reaction product in supporting cells is restricted to microvillar and plasma membranes. The anti-S-100 beta antiserum used in these studies does not bind to basal cells of the olfactory epithelium or to cells of the olfactory glands, whereas it binds to Schwann cells of the olfactory nerve. An anti-S-100 alpha antiserum does not bind to cellular elements of the olfactory mucosa, Schwann cells, or axons of the olfactory nerve. The present data provide, for the first time, evidence for the presence of S-100 beta beta protein in mammalian neurons (olfactory cells).     

The dynamics of latent inhibition in rats under the action of substance P]

The role of substance P in latent inhibition was studied in experiments on rats. Administration of neuropeptide during pre-exposition of conditioned stimulus and before conditioning disturbed all signs of latent inhibition: level of reproduction, retention and resistance to amnestic action of conditioned reaction in the task of passive avoidance. Single administration of haloperidol before learning prevented the disturbance. Significance of hyperfunction of substance P in selective attention and pathogenesis of schizophrenia is discussed.     

Analysis of the process of learning in the formation of the conditioned reflex of avoidance in rats

During acquisition of avoidance conditioned reflex (CR) in shuttle box by electric shock it is shown that the performance of that defence reaction is induced by the joint action of two factors: general arousal of animals and motivation. Motor activity of rats in an "open field", the number of short-latency (2s) and intersignal responses during formation of the avoidance CR are in index of the general arousal of rats. An artificial increase in the general arousal of animals by caffeine induces acceleration of CR performance. A constant level of the general arousal of rats is one of the reasons that oxytocin does not influence the rate and dynamics of the avoidance CR performance in rats.     

Regulation of Nervous System-Specific S-100 Protein and Enolase Levels in Adipose Tissue by Catecholamines

The effect of catecholamines on the levels of S-100 protein and nervous system-specific enolase (NSE) in epididymal adipose tissue of Wistar rats in vivo was examined by sensitive enzyme immunoassay methods. Soluble S-100 protein levels in the adipose tissue of 9-12-week-old rats (1.46 +/- 0.19 microgram/mg protein) were decreased to less than 50% of those of controls by serial injection (for 4-7 days) of epinephrine (0.1 mg/day) or norepinephrine (0.15 mg) with, however, little effect on the levels of membrane-bound (pentanol-extractable) S-100 protein. A significant decrease in the soluble S-100 protein levels was observed at 2 h after a single injection of epinephrine (1.04 +/- 0.13 microgram/mg protein). On the other hand, levels of NSE subunit (gamma subunit or 14-3-2 protein) in adipose tissue (0.51 +/- 0.03 gamma gamma-equivalent pmol/mg protein) were increased to 170% of control by serial injection (for 7 days) of epinephrine or norepinephrine with little change of the level of enolase alpha subunit on a mg protein basis. Isoproterenol had no apparent effect on the levels of soluble S-100 protein and NSE subunit. These results suggest that the levels of S-100 protein and NSE in adipose tissue are regulated by catecholamines.     

Effect of a cyclic enkephalin analog on the protein content in the hippocampal neurons of rats during the acquisition of a 2-way avoidance conditioned reflex

The protein content has been determined by means of cytointerferometry in neurons of fields CA-1 and CA-3 of the dorsal hippocampus in rats, which were trained in a conditioned reflex of two-way avoidance (CRTA) with the action of subcutaneously injected enkephalin cyclic analogue (ECA) in a dose 10 mkg. It has been found that after ECA injection the protein content in the neuronal nuclei of the hippocampal CA-3 field reduces. The acceleration of the CRTA elaboration occurring during the action of ECA is accompanied by a drastic increase of the protein content in the neuronal nuclei of the CA-3 field. The ECA administration to the rats of the active control groups to which were presented the same number of unpaired conditioned and unconditioned stimuli as during the CRTA elaboration also enhances the protein content in the neurons of the CA-3 field. The rats of all investigated groups in the neurons of the CA-1 field display no such significant shifts. The conclusion has been drawn that ECA produces a regulating influence on protein metabolism in hippocampal neurons depending on their functional state.     

Neurochemical mechanisms of the septum in food getting conditioned responses in rats]

The influence of microinjections of monoamines and of glutamic acid into the lateral zone of the septum on a food-procuring conditioned reaction was studied in experiments on rats. Dopamine does not change, while noradrenaline, serotonin and glutamic acid increase the magnitude and number of conditioned food-procuring movements and substantially lengthen the reflex latency. The effects of serotonin are achieved through D-serotonin-, and of noradrenaline, through L-adrenoreactive structures of the neuronal systems of the septum. The influence of glutamic acid on the rat food-procuring conditioned reactions is not linked with the action on the serotonin- or adrenoreactive structures of the septum neuronal systems.     

Characteristics of the psychotropic spectrum of action of mebicar

Under group interaction in cats, a new Soviet tranquilizer mebicar eliminates fear-alarm induced by stimulatin of the emotiogenic zone of the hypothalamus. This action is not associated with myorelaxant or hypnotic action. Mebicar decreases the brain noradrenaline level, exerts no effect on the dopaminergic systems, increases the brain serotonin level, and does not elicit cholinolytic action.     

IMMUNOHISTOCHEMICAL STUDIES OF S-100 PROTEIN DURING POSTNATAL ONTOGENESIS OF THE BRAIN OF TWO STRAINS OF RATS

Abstract— We have studied the dynamics of the appearance of cells reacting positively with anti-S-100 protein antiserum, during postnatal neurocytogenesis in the brain of rats of two strains differing in their susceptibility to sound stimuli. The postnatal time of appearance of cells reacting positively with anti-S-100 protein antiserum was somewhat later in rats susceptible to sound-induced seizures than in sound-resistant rats. These differences concerned mainly the cerebral cortex of 12-day-old rats. By day 21 of postnatal life these differences had disappeared. In subcortical structures of the brain, S-100 protein was first found on the 4th to the 5th day of life and the rate of appearance of cells containing this protein was similar in the two strains.     

Participation of the central noradrenergic system in the mechanisms of latent inhibition

Male Wistar rats were learnt to conditioned reaction of passive avoidance 10 days after intraperitoneal administration of 50 mg/kg of specific neurotoxin DSP4. The character of conditioned reaction reproduction, duration of its conservation and its stability against amnestic processing were analyzed. It has been found that reduction of activity of noradrenergic coerulo-cortical system does not influence the conditioned reaction reproduction but inhibits its spontaneous extinction and prevents amnesia development. The obtained data are discussed in aspect of central noradrenaline participation in latent inhibition mechanisms.     

Spectrum of psychotropic effects and mechanism of action of ultra low doses of the antibodies to S-100 protein (proproten)

Proproten contains ultra-low doses of affinity purified antibodies to S-100 protein dynamized according to the rules of homeopathy. S-100 is regulator of brain integrative activity and takes part in synaptic processes. In experiment on outbred rats proproten demonstrates significant anxiolytic, antidepressant and antiamnestic effects after single and repeated administration. Proproten is similar to the well-known reference preparations diazepam, amitriptyline and piracetam in activity. Proporten's advantage over these drugs is no sedative, myorelaxation and amnestic effects. Psychotropic effects of proproten are likely to result from modulation of synaptic transmission in limbic structures of brain.     

Various neurochemical mechanisms for the production of conditioned reflexes of various biologicals modalities at the level of the caudate nucleus]

Microinjection of noradrenaline in to the head of the caudate nucleus failed to influence the latent time of the conditioned reaction of avoidance and the muscle tone, but limited the motor activity and considerably increased the value and the latent time of the food-procuring reflex. Serotonin failed to influence the latent time of the conditioned defence reflex and did not alter the motor activity of rats; however, it shortened the latent period of the conditioned motor-food reflex and markedly stimulated the food-procuring reaction. Dopamine inhibited the conditioned food and defence reflex, but markedly stimulated the spontaneous motor activity of rats. The data obtained pointed to differences in the neurochemical mechanisms realizing the conditioned reflex reactions of different biological modality at the level of the caudate nucleus of rats.     

Immunocytochemical localization of S-100 protein in astrocytes and Müller cells in the rabbit retina

Summary The localization of S-100 protein was studied in histological sections of retinae from adult rabbits. By use of double-immunolabeling techniques it was shown that most but not all radially oriented vimentin-positive Müller cells were co-labeled by an antiserum to S-100 protein. Glial fibrillary acidic protein-positive astrocytes, which in the rabbit retina are restricted to the medullary rays formed by myelinated optic nerve fibers, consistently showed S-100 protein immunoreactivity. The present report shows that, with respect to S-100 protein staining, Müller cells represent a heterogeneous population of glial elements.     

Immunocytochemical study of the distribution of S-100 protein in the parathyroid gland of rats and guinea pigs

The distribution of S-100 protein in the parathyroid cells of normal and hypercalcaemic rats and guinea pigs was investigated. Previous studies had shown that the applied antibodies detect only the beta subunit of S-100 protein. S-100 protein was found in all parathyroid cells of rats aged between 1 and 720 days. In adult guinea pigs, S-100 protein was detectable in only a small proportion of parathyroid cells. The level of S-100 protein in individual cells exhibited considerable variation, particularly in guinea pig. Hypercalcaemia did not affect the distribution of S-100 protein in the parathyroid cells of either rats or guinea pigs. In both species, the presence of small groups of parathyroid cells in the central fragments of thyroid lobes was often noted.     

Gastric erosions induced by intracisternal thyrotropin-releasing hormone (TRH) in rats

Intracisternal injection of TRH (1 microgram) under light ether anesthesia induced within 4 hr gastric lesions in 24-hr fasted rats maintained unrestrained at room temperature. Saline, ovine corticotropin-releasing factor (oCRF, 10 micrograms), or human pancreatic growth hormone-releasing factor [hpGRF(1-40), 10 micrograms] tested under the same conditions did not modify the integrity of the gastric mucosa. TRH injected intravenously (100 micrograms/kg) proved to be ineffective. The production of gastric erosions elicited by intracisternal TRH (0.1-1 microgram) or by a stabilized TRH analog, RX 77368 [pGlu-His-(3,3'-dimethyl)-ProNH2, (0.01-0.1 microgram)] was dose-dependent. RX 77368 shows an enhanced potency over TRH. TRH action on gastric mucosa was reversed by atropine, omeprazole and cimetidine. These results demonstrate that TRH, unlike the other hypothalamic releasing factors CRF or GRF, is able to act within the brain to cause the formation of gastric erosions probably through mechanisms involving changes in gastric acid secretion. Intracisternal injection of TRH or its potent analog RX 77368 appears also as a new, simple method to produce centrally mediated experimental gastric erosions in 24 hr-fasted rats.     

Level of neuroactive steroids in the brain, and gender-related differences in formation and decrease of conditioned reflex in rats

We investigated gender-related differences in dynamics of the brain sexual steroids during learning and the decrease of conditioned reflex in the modeling experiment. It was revealed that, before training to conditioned reflexes, females manifested a greater anxiety than males. Significant differences between males and females in formation of the conditioned reflex of passive avoidance were not revealed, whereas the conditioned response decrease were by 2-3 days faster in male rats than in females. It was revealed that there was an increase of testosterone content in various structures of the brain, especially in hippocampus and frontal cortex with its constant level in the blood plasma in learning conditioned response of passive avoidance in male adult rats. Also an increased estradiol concentration was found in females' amygdale, while increased value of estradiol was detected in hippocampus and the singular cortex in decrease of the conditioned response of passive avoidance. In blood plasma, the testosterone level was not changed, and the estradiol concentration was reduced significantly after the decreased conditioned reflex. Different dynamics of changes in the levels of sex steroids in the brain and the blood plasma can indicate a probability of their formation in nervous tissue. The correlation analysis confirms the conception about selective involvement of the brain's testosterone and estradiol in the specific structures in realization ofthe learning and memory processes in adult male and female rats.     

Effect of acute melipramine administration on motor activity and defensive conditioned reflexes of passive and active avoidance in rats

The administration of threecyclic antidepressant melipramine to Wistar rats (15 mg/kg, intraperitonaly, 2 h before of experiments) increases time of an "open field" centre leaving. Thus melipramine does not influence horizontal and vertical activity, and also the number of bolus. At the development of a passive avoidance conditioned reflex melipramine significantly slows down realization of a unconditional mink reflex by untrained rats, increasing the latency of call in a dark compartment of the chamber. After training significant deterioration of a reflex reproduction is observed. At research of a defensive conditioned reflex of active avoidance melipramine worsens both development and reproduction of a reflex. The comparative analysis of the literary data of imipramine action on uptake of serotonine and noradrenaline and the analysis of the literary data on a role of these systems in the processes of learning and memory allows to suggest, that the effect of melipramine is connected mainly to amplification activity of serotoninergic system of a brain. It is supposed, that acute administration of melipramine creates emotionally negative state, worsens processes of learning and memory, strengthening mainly activity of a brain serotoninergic system. It specifies that serotoninergic system of a brain is system of punishment. Its activation interferes with formation and consolidation of connections between conditional and unconditional irritation.     

Immunocytochemical study of the distribution of S-100 protein in the parathyroid gland of rats and guinea pigs

Summary The distribution of S-100 protein in the parathyroid cells of normal and hypercalcaemic rats and guinea pigs was investigated. Previous studies had shown that the applied antibodies detect only the subunit of S-100 protein. S-100 protein was found in all parathyroid cells of rats aged between 1 and 720 days. In adult guinea pigs, S-100 protein was detectable in only a small proportion of parathyroid cells. The level of S-100 protein in individual cells exhibited considerable variation, particularly in guinea pigs. Hypercalcaemia did not affect the distribution of S-100 protein in the parathyroid cells of either rats or guinea pigs. In both species, the presence of small groups of parathyroid cells in the central fragments of thyroid lobes was often noted.