[Individual differences in the reactions to acute stress related to behavioral type. Resistance (predisposition) to behavioral and sleep disorders].

Resistance (predisposition) to behavior and sleep disturbances after acute stress was studied in rats with different types of behavior in open field and forced swimming tests. The highest resistance to stress (the least alterations of behavior and sleep parameters) was found in rats with the active type of behavior, the least resistance to stress--in the middle group, and rats with the passive type of behavior held the intermediate position. The comparison of the present data with previously obtained results showed a positive correlation between the resistance to stress and the resistance to circulatory cerebral hypoxia induced by bilateral common carotid arteries occlusion.

[Effect of substance P on survival of rats after cerebral ischemia: the effect depends on behavior type].

In rats with different behaviour types in tests of "open field" and "forced swimming", influence of intraperitoneal administration of P-substance (PC) neuropeptide to survival and structural-metabolic changes in brain after double-sided ligating of carotid arteries. It was established that PC exerts different influence on stability to circulating cerebral hypoxia according to behaviour types: it increases stability in rats with passive behaviour type, decrease stability in rats with active behaviour type and does not influence on rats with middle behaviour type. Results shows the necessity of individual approach to peptide use with the view to increase stabilization to cerebral ischemia.

[The respiration and oxidative phosphorylation of the brain mitochondria in rats with different types of behavior].

Respiration and oxidative phosphorylation of brain mitochondria were studied in outbred rats with different types of behaviour in open-field test and in forced swimming test. It was found that in rats with "active" type of behaviour (with high locomotor activity and low level of depressiveness) the brain mitochondria have at succinate oxidation a higher rate of respiration in active metabolic state and in presence of uncoupler 2,4-DNP, and a higher rate of ADP phosphorylation than in rats with "passive" type of behaviour (with low locomotor activity and high and moderate levels of depressiveness). Thus rats with active type of behaviour have a higher succinate oxidase activity than rats with passive type of behaviour.

[Changes in the oxygen tension level in different brain structures of rats in the waking-sleep cycle].

Changes of oxygen tension level (pO2) in the visual cortex, dorsal hippocampus, lateral hypothalamus and central grey substance were studied during wake-sleep cycle in rats. The dependence was established of pO2 level changes on the character of behavioural reactions and on the accompanying hippocampal EEG activity: during orienting-investigatory and active defensive behaviour and also during paradoxical sleep, accompanied by hippocampal theta rhythm, pO2 level increased; during passive-defensive behaviour "freezing" reaction accompanied by desynchronization of the hippocampal rhythmic, the level of pO2 decreased. The obtained data confirm Routtenberg hypothesis about two relatively independent systems of ascending activation with different types of hippocampal EEG activity and supplement it with a thesis that the activity of these systems is accompanied by different shifts of brain oxidative metabolism.

[Effects of intrauterine alcohol intoxication on the function of the central nervous system in the progeny].

Behavior of mature rats, who had been exposed antenatally to intrauterine alcoholic intoxication, was studied in the open field settings, unavoidable swimming and Simonov's emotional resonance situations; their conditioned reflexes of passive and active avoidance were trained, arterial blood pressure was measured, and sleeping patterns examined. It was demonstrated that animals' orientation/exploration activity was reduced, while passive behavior and fear-associated emotions became more prominent, conditioned reflexes were more difficult to form, vegetative autoregulation was disturbed, and insomniac disturbances were in evidence as a result of intrauterine alcoholic intoxication. It is suggested that the above-listed disorders are rooted in hypoxic cerebral changes, induced by pathogenic effects of alcohol on the embryonal and fetal central nervous system.

[Pharmacological correction of experimental alcoholic embryopathy].

In the experiments on the progeny of ethanol-exposed rats it was shown that consumption of 15% alcohol instead of water during pregnancy resulted in the worsening of shuttlebox avoidance learning and decrease in succinate dehydrogenase activity in the visual and sensorimotor cortex. These data are indicative of cerebral hypoxia during embryogenesis. The injection of synthetic opioid peptide dalargin during critical periods of development (at the end of embryogenesis and early ontogeny) prevented partially the disturbances of higher nervous activity and tissue breathing which were induced by alcohol intoxication.

[The electrographic picture of sleep as affected by a thyroliberin analog].

The neurotropic effects of pyroglutamyl-seryl-phenylalanine amide, the thyrotropin-releasing hormone analog, have been studied in experiments on male rats. Electrodes were implanted in the hippocamp and the optic cortex for registration of electroencephalograms. The analog administered intraperitoneally decreased the time of onset of slow sleep increasing the duration of this phase.

[Peptide therapy of sleep disorders in neurotic rats].

As a result of chronic stress, anxiety appeared in the rats behaviour, motor activity increased, heart rate quickened, blood pressure raised, conditioned instrumental alimentary reflexes missed, the duration of deep phases of sleep lowered, time of falling asleep became longer, the number of awakening increased. The change in quantitative characteristics of sleep was accompanied by its worsening, especially of rapid sleep. Administration of substance P (SP) eledoisin hexopeptide (EH) (250 mcg/kg), 100-200 mcg/kg of delta sleep peptide and 10 mcg/kg of ethylcrotyl barbiturate improved the rats behaviour and sleep parameters.

[Neuroendocrine effect of thyroliberin and its analogs].

In experiments on rats, thyroliberin (TRH) and its analogue pyroglutamyl-histidyl-prolinamide stimulating effects on the CNS were shown. They produced a decrease in some phases of the sleep duration (particularly, in the deep one) and augmented the awakening period. At the same time, the antagonistic effect of these compounds with respect to nembutal anaesthesia was seen.

[Effect of thyrotropin releasing hormone and its analogs on sleep and wakefulness cycles].

A comparison of the biological activity of the thyreotropin-releasing hormone and its two analogs was carried out as to their ability to stimulate the secretion of thyreothropin from the pituitary body in rats, as well as of their effect on behavioural and electrographic sleep pattern. Among the studied drugs only the thyreotropin-releasing hormone exhibited a clearly pronounced biological activity. Its both analogs were ineffective.

[Conditioned reflex, electrographic and mediator-humoral changes during intermittent hypokinesia of different duration in rats].

Intermittent hypokinetic stress in rats, lasting from 1 to 6 weeks was attended by a complex of shifts of behavioural, conditioned, bio-electrical and mediator-humoral parameters. They considered as an evidence of the changes occuring in the tonic level of emotional state. Different phases of emotional state follow one another with the progress of hypokinesia.

[Dynamics of visual cortex and hippocampal electrical activity during prolonged immobilization].

As the result of chronic immobilization of rats, their EEG of the visual cortex and hippocampus showed an increased energetic capacity predominantly in the theta-frequency range, a lowered level of synchronization in response to light, reduced sleep duration due to the late falling asleep and waking at different stages. Their sleep became more superficial, the duration of its deeper stages (especially of the paradoxical sleep) decreased, the correlation between the sleep depth and muscular tone and heart-rate was disturbed. The rate of these disorders depended on individual characteristics of the animals nervous system.

[Activation of hypersynchronous discharges in the visual cortex using corazole].

A study was made of the firing (extracellular records) of the rabbit visual cortex cells during hypersynchronous rhythmics of the wave-peak type, provoked by intravenous injection of subconvulsive doses of corasol. The analysis suggests that the wave-peak discharge results from synchronous alternation of depolarization potentials and long periods of postsynaptic inhibition in most of the cortical elements. In the course of involvement of new elements in the reaction, there is an increase in the probability of appearance of populations with a different frequency of discharge; this is one of the causes of discontinuation of the paroxysmal rhythm following small doses of corasol.

[Sensory after-discharges of the rat visual cortex during elaboration and extinction of a temporary connection].

Sensory after-discharges (SAD) in the rat's visual cortex became more intense at the background of an unconditioned drinking reaction. During the elaboration of a conditioned reflex to light (ten successive flashes of which the last five were reinforced) the SAD enhancement proceeded in two stages; the first coincided with the reinforcement, the second was developing in the phase of a stable conditioned reflex to the second or third flash of the rhythmic series. When reinforcement was omitted in a test with acute extinction.

[Electrographic activity in rats during elaboration of fine distinctions].

A definite correlation has been found between the background EEG, the sensory afterdischarge (SAD) of the visual cortex and the nature of the animals' behaviour. Calmer rats with a well pronounced SAD exhibited activation of a certain type of hygienic movements, as fine differentiations were presented. As a rule, the movements were accompanied by EEG synchronization.