EARLY POSTNATAL DYSFUNCTIONING OF THE BRAIN MUSCARINIC CHOLINERGIC SYSTEM AND THE DISORDERS OF FEAR-MOTIVATED LEARNING AND MEMORY.

The aim of the study was to investigate the early postnatal dysfunctioning of the brain muscarinic cholinergic system as a major factor in the development of cognitive disorders similar with somewhat is noted in animal models of depression and in patients with Major Depressive Disease. The present study examined the processes of learning and long-term retention of information obtained in the two important tasks of non-declarative memory - active avoidance, motivated by foot shock-induced fear, and the elevated plus-maze, based on the natural fear.Experiments were carried out on male white wild rats (n=60).

ACQUISITION AND CONSOLIDATION OF TWO-WAY ACTIVE AVOIDANCE IN THE HIGH IMMOBILIZATION "DEPRESSIVE" RATS.

Present study investigated possible changes in acquisition and consolidation of associative memory in high immobilization "depressive" and low immobilization "non-depressive" rats. Question is very topical because understanding the character of learning and memory disturbances, one of symptoms of major depressive disease, is very significant for more intimate definition of the pathophysiology of major depressive disorder and appropriate searching the ways of its correction. Selection of rats according to the level of immobilization was made by means of forced swim test.

CHARACTER OF THE CHANGES IN FEAR MOTIVATED DECLARATIVE MEMORY IN THE HIGH IMMOBILIZATION "DEPRESSIVE" RATS.

Present study investigated possible differences in the learning and memory of declarative memory task in rats selected according to the differences in immobilization response that is in high immobilization "depressive" and low immobilization "non-depressive" rats. Understanding the character of learning and memory disturbances in basal conditions of animal models of depression is still very topical for more intimate definition of the pathophysiology of major depressive disorder and appropriate searching the ways of its correction. Experiments were carried out on the adult white wild rats (with the weight 200-250 g, n=20).

HYPOTHALAMIC OREXINE SYSTEM ACCELERATES REGULATION OF SLEEP HOMEOSTASIS AND SLEEP-WAKEFULNESS CYCLE RECOVERY FROM BARBITURATE ANESTHESIA-INDUCED ARTIFICIAL SLEEP.

The work was aimed for the ascertainment of following question - whether Orexin-containing neurons of dorsal and lateral hypothalamus and brain Orexinergic system in general are those cellular targets which can accelerate recovery of disturbed sleep homeostasis and restoration of sleep-wakefulness cycle behavioral states from barbiturate anesthesia-induced artificial sleep. Investigation was carried out on 18 wild type white rats (weight 200-250gr). Different doses of Nembutal Sodium were used for the initiation of deep anesthesia.

Influence of serial electrical stimulations of perifornical and posterior hypothalamic orexin-containing neurons on regulation of sleep homeostasis and sleep-wakefulness cycle recovery from experimental comatose state and anesthesia-induced deep sleep.

The work was aimed for the ascertainment of following question - whether Orexin-containing neurons of dorsal and lateral hypothalamic, and brain Orexinergic system in general, are those cellular targets which can speed up recovery of disturbed sleep homeostasis and accelerate restoration of sleep-wakefulness cycle phases during some pathological conditions - experimental comatose state and/or deep anesthesia-induced sleep. Study was carried out on white rats. Modeling of experimental comatose state was made by midbrain cytotoxic lesions at intra-collicular level.

Insomnia in a displaced population is related to war-associated remembered stress.

Although traumatic events are presumed to cause sleep disturbances, particularly insomnia, sleep in populations subjected to forced displacement has received little attention. The present study examined the prevalence of insomnia and associated factors in internally displaced persons (IDPs) from Abkhazia 15 years after displacement to Tbilisi. Detailed subjective information about sleep-wake habits, sleep-related and stress-related parameters were obtained from 87 IDPs categorized into good sleepers and insomniacs.

Changes of open field behavior in animal model of depression.

Animal model of depression was developed by means of chronic exposure of rat pups to anticholinergic drugs (Atropine, Scopolamine) during the early life period from postnatal day 7 (P7) and/or 14 (P14) to P21 and/or P28, respectively. Such procedure resulted in lasting behavioral changes that were evident long after drug discontinuation and persisted at mature age (2-3 month period). Behavioral changes included most indices of open field behavior.

Changes of locomotor, exploratory and emotional behavior in animal model of depression induced by deficiency of brain monoamine content.

The character of changes of open field behavior was not studied extensively in animal model of depression with deficiency of brain monoamine/serotonin content and obtained results are controversial. Both, enhancement and invariability of locomotor activity has been obtained. Additional investigation of this question is motivated also by insufficient study of exploratory and emotional behaviors in animal model of depression of this type.

Effects of trihexyphenydil, the structural analog of phencyclidine, on neocortical and hippocampal electrical activity in sleep-waking cycle.

Finding about structural and functional relation between NMDA receptors specific binding and phencyclidine sites was very important for a possible modulation of NMDA receptors' function. We have therefore got interested what would happen with EEG and vegetative patterns of PS in the case when NMDA receptors function is modulated by blocking of phencyclidines' site. Consequently, we studied the effects of Trihexyphenydil, the structural analog of phencyclidine, on neocortical and hippocampal electrical activity in SWC.

Influence of diazepam on different behavioral states of sleep-waking cycle.

Diazepam is a widely used benzodiazepine. Their prolonged usage leads to deterioration of cognitive functions and to the reduction of the level of vigilance what is explained by hypnotic effect but not by anxiolytic action of this drug. The novelty of our investigation is the elucidation of whether diazepam produces slow wave sleep reduction likely to the other benzodiazepines and if so what is the bases of positive therapeutic effect of diazepam in insomniac patients.

Septo-hippocampal cholinergic/gabaergic relationship and sleep-waking cycle.

There is controversy in the literature in the results of various septal lesions on the sleep-waking cycle (SWC) ultradian structure. Current investigation was aimed to study the effects of interruption of septo-hippocampal cholinergic/GABAergic afferentation on the ultradian structure of SWC and on PS major indices. Experiments were carried out on 12 adult cats, operated under overall anesthesia (Nembutal, 35-40 mg/kg).

The influence of electrocoagulation of the septum and section of the entorhinal cortex on general behaviour and memory in cats.

In chronic experiments on cats it was shown that the lesion of the medial part of the septum does not result in the "septal syndrome"; the ratio of the different sleep-wakefulness cycle phases remains within the baseline values; the acquisition, retrieval and extinction of instrumental alimentary conditioned reflexes proceed normally; the delayed conditioned reflexes are impaired. Massive septal lesion, including its lateral part, leads to the development of the "septal syndrome"; there are changes in the structure and percentage of the different sleep-wakefulness cycle phases; the acquisition and extinction of instrumental alimentary reflexes with the sound discrimination are markedly retarded; the performance of delayed conditioned reflexes is completely destroyed. The section of the entorhinal cortex produces an increase in the number of repeated errors and perseverative movements during performance of instrumental alimentary reflexes, the deceleration of the acquisition and extinction of instrumental alimentary reflexes, complete disturbance of the delayed conditioned reflexes and does not affect the sleep-wakefulness cycle.