Parameters of stress response at various stages of postresuscitation period.

Transient circulatory arrest (10 min) was followed by changes in rat adrenals and thymus and a decrease in blood calcium and protein contents typical of stress response. Maintenance under unfavorable conditions for a long time also produced changes in stress-target organs accompanied by a considerable shift in functional state of the central nervous system manifested in enhanced behavioral response to exogenous stimulation.

Behavioral reactions of rats in the early postresuscitation period after systemic circulatory arrest of different duration.

Rats were exposed to systemic circulatory arrest for 10, 12, and 15 min. During the first 10 days after resuscitation exploratory activity of animals depended on the duration of systemic circulatory arrest and was determined by two opposite factors: high reactivity of the central nervous system contributing to intensification of exploratory activity, and impaired general state of survivors (inhibition of animal behavior).

Some reasons for modifications of rat's conditioned behavior after resuscitation.

In rats survived systemic circulatory arrest and resuscitation, pathological changes such as increased excitability of the central nervous system and decreased volume of simultaneously acquired information considerably modulate conditioned activity. The interaction between these factors facilitates learning after formation of targeted behavioral pattern.

[Effect of perftoran on post-resuscitation recovery of the central nervous system].

The effect of perfluorane on survival and restorative process in the brain were studied in rats subjected to 12-min arrest of systemic circulation. Perfluorane in a single dose of 5-10 ml/kg was injected intraperitoneally 30 min after the beginning of reanimation. The drug did not affect the postreanimation death of animals and time course of neurologic deficiency disappearance.

[The delayed effects of systemic circulatory arrest on the free-radical processes in the brain structures of rats with different types of behavior in the emotional resonance test].

Male Wistar rats with different types of behavior in "emotional resonance" test ("active" and "passive") were studied one week after the global ischemia induced by cardiac arrest. Recovery of some physiological functions as well as free-radical-mediated processes and NO-synthase activity were studied in cerebral structures and blood serum. The "open-field" behavior normalized more rapidly in the "active" rats than in the "passive" ones, though the time course of the neurologic deficit compensation did not differ in these groups.

[Post-resuscitation neurosomatic deviations and the feasibility of their correction with a drug of metabolic action].

Circulation in white rat males was stopped for 10 minutes by ligation of the intrathoracic vascular bundle of the heart. Proxipin in a dose 10 or 20 mg/kg was injected i.p.

[Effects of active behavior in the postresuscitation period on the functional and morphological characteristics of the brain].

Efficacy of prolonged (days 10-60 after resuscitation) regular activation of behavior by labyrinth training of 4-staged food search conditioned reflex is studied in rats subjected to 15-min circulation arrest. This training affected the function of the central nervous system, which manifested by decreased anxiety and a higher activity in the open field test. This functional exercise prevented fall-out of neurons in the fifth layer of hemispheres, of cerebellar Purkinje's cells, and of pyramidal neurons in hippocampal sector CA1.

[The effect of systemic circulatory arrest on the process of free-radical oxidation and on NO-synthase activity in the brain structures of rats of different behavioral types in an emotional resonance test: the acute effects].

Free radical-mediated processes and NO-synthase activity were studied in cerebral structures and blood serum of male Wistar rats with different types of behavior in emotional resonance test one hour after global ischemia induced by cardiac arrest. Oxidative stress accompanied by loss in NO-synthase activity was revealed in cerebral cortex after the ischemia. The oxidative stress was also evident in cerebellum and to a lesser extent in hippocampus.

Prophylaxis of encephalopathies and risk factors of atherogenesis development in the postresuscitation period in rats by means of succinic acid.

The effect of oral administration of succinic acid was studied in 66 rats exposed to 10 min cardiac arrest with further resuscitation. A total of 30 mg/kg of the drug were administered daily for 5 days starting with day 3 up to day 7 after resuscitation. The experiments have revealed that treatment with succinic acid caused normalization of the orienting behavior in an 'open field' test, decrease of the intensity of response to electric shock, normalization of free radical formation in the brain and serum and reduced cerebral morphological changes.

Postresuscitation changes in brain free radical-mediated processes and nitric oxide synthase activity in rats: effects of individual behavior in "emotional resonance" test.

Effects of 7-min cardiac arrest and individual behavior on free radical-mediated processes and nitric oxide synthase (NOS) activity was evaluated in brains of male Wistar rats one hour and one week after resuscitation. "Emotional resonance" test was used for the behavioral selection of rats. The test includes factors of significance for rats: the choice between large and lighted or small and dark space as well as signals of pain of another rat.

[The effect of succinic acid on postresuscitation pathology of the CNS and of the body as a whole].

The effect of oral succinic acid was studied in rats exposed to 10-min heart arrest followed by resuscitation. The drug was administered for 5 days in a dose of 30 mg/kg starting from day 3 up to day 7 after resuscitation. Succinic acid was found to normalize the orientation and exploration behavior of rats in the "open field" test, decreased the intensity of response to stress (electric shock), and normalized the radical formation in the brain tissue and blood serum, thus reducing the morphological changes in the brain.

[Delayed postresuscitation degenerative changes in the brain and ways of studying their pathogenesis].

Experiments with rats resuscitated after clinical death compatible with a complete and relatively rapid recovery of the neurologic status proved that prolonged (a follow-up of up to 9 months) and varying in time changes in a number of parameters of the higher nervous activity and behaviour occur in the postresuscitation period. Postresuscitation changes in behaviour correlate with the data on the degenerative changes in a number of cerebral structures of resuscitated rats progressing over 9 to 12 months. The available data of functional and morphological studies indicate the possibility of development of latent slowly progressing degenerative changes in the CNS of the organisms surviving clinical death and resuscitation.

[Effects of sodium succinate on functional, biochemical and morphological indicators of CNS repair in rats after 10-minute circulation arrest].

Therapeutic effect of sodium succinate on various functional, biochemical, and morphological parameters of CNS repair was studied in experiments on rats exposed to 10-min circulation arrest. The first series of experiments was devoted to studies of the effects of the drug, injected intraperitoneally directly after recovery of effective cardiac activity and during the subsequent 5 days in doses 20, 100, and 200 mg/kg, on the survival and recovery of the external neurologic status. The dose of 20 mg/kg proved to be the most effective.

[Effect of the tranquilizer gidazepam on the behavioral reactions of rats in the first weeks after resuscitation].

The experiments have indicated that the first week of postresuscitation is marked by enhanced goal-investigating behaviour in the open field, by the accelerated learning of an operant reflex, and by decreased anxiety in the conflict situation test in male rats undergone a 10-min arrest of systemic circulation. There was a depressive behavior in the open field following 6-8 weeks with the normalization of operant reflex learning and the level of anxiety in the conflict test situation. Gidazepam (3 mg/kg, i.

[The characteristics of the adaptive behavior, neurological recovery and a morphometric analysis of the cerebral cortex in rats in the postresuscitation period].

Rats recovered after a 10-min circulation arrest, were examined in the early postresuscitation period (within 10-12 days after resuscitation) in an open field (OF) test and during elaboration and reproduction of passive avoidance conditioned reflex (PACR); morphometric analysis of sensorimotor brain cortex was performed on days 4, 7, 14, and 30 after resuscitation. It has been shown that directly after compensation of external neurological deficit which took place in the majority of animals within 3 days the process of adaptation to new situation (OF test) in resuscitated rats, unlike the intact ones, was associated with high motor activity and not with the elaboration of stable correlations between various behavioral acts. At the same time disorders in learning and memory have been observed in PACR test.

The dynamic of thermal fields of the brain of rats in the late post-resuscitation period under stress.

The temperature topography of the cerebral cortex of rats following clinical death and resuscitation was investigated with the technique of thermoencephaloscopy. Complete restoration of the neurological status of the animals was achieved over the course of one to two days. Marked disturbances in the background thermal maps and the thermal reactions of the cerebral hemispheres induced by a stressor were identified in the remote post-resuscitation period (up to two months).

[The dynamics of the brain heat fields of rats in the late postresuscitation period during stress].

By thermoencephaloscopy method the temperature relief of the rats cerebral cortex was studied after the clinical death and reanimation. The rehabilitation of the animals neurological status was completed in 1-2 days. In the remote postresuscitation period (up to 2 months), expressed disturbances were revealed of the background thermomaps and of thermal reactions of the cerebral hemispheres, evoked by the stress influence.

[The indices of rat open-field behavior and the characteristics of the survival and functional recovery of the CNS following circulatory arrest].

In experiments on rats it has been shown that for prognostication of successful reanimation after the clinic death of different duration (5, 10, 15 min) correlative interactions between the parameters of behaviour in the open field before blood circulation cessation are more essential than their absolute values. Highly significant correlation coefficients (0.7 and more) between the majority of behaviour parameters were typical for the group of animals which had survived after a prolonged blood circulation cessation (15 min); for rats rehabilitated after 5- and 10-min cessation of the blood circulation--between the characteristics reflecting, basically, the motor-investigating component of the behaviour.

[Changes in the sensitivity of the central nervous system to fenazepam at different stages of the recovery period after systemic circulatory arrest in rats].

Chronic experiments were conducted on rats subjected to 10-minute circulatory arrest to study the effect of intraperitoneal phenazepam (2 mg/kg) injection in various periods after resuscitation on some behavior indices. It was found that the changes in the quantitative (the degree of the effect) and qualitative (the extent of the effect) manifestations of the tranquilizing effect of phenazepam were determined by the different stages of restoration (from 1 to 21 days) after resuscitation. The results provide evidence of a definite stage character in the reactivity of the central nervous system in relation to pharmacological effects after resuscitation and, possibly, may reflect the functional reorganization of the work of the receptor complex and ion conductivity in the postresuscitation period.

[The postresuscitation changes in the permeability of the hemato-encephalic barrier and their possible pathogenetic significance].

Experiments were conducted on rats with temporary (10-min) clamping of the thoracic vascular bundle and subsequent resuscitation to study the permeability of the blood-brain barrier (BBB) to plasma albumins and globulins and to blood plasma immunoglobulins in different stages of the postresuscitation period. Mild increase of BBB permeability was detected 3 minutes after the beginning of recirculation. Permeability increased markedly in 24 hours and continued growing by the 72nd hour.

[Structural and functional status of chromatin in the cerebral cortex neurons after circulatory arrest in the rat].

On the 4th day after revivification of rats, subjected to blood circulation arrest, transcriptional activity of chromatin has been evaluated after Moor's method and the state of histones has been investigated in neuronal nuclei of the III, IV and V layers of the cerebral cortex sensomotor area. Both in intact animals and those, subjected to clinical death, the neurons of the cortical layers examined sharply differ in their transcriptional activity of chromatin. The lowest level of labelling is revealed in the IV, the highest--in the V layer.

[Changes in the spreading depression wave in rats in the postresuscitation period].

Functional state of the rat brain cortex after a 10-minute arrest of blood circulation was studied by means of the spreading depression wave, the latter leading to significant energy expenditures and being accompanied by a transmitter output and changes in extra- and intracellular ion concentration. The changes in the spreading depression wave took place at different stages of the postresuscitation period (2 hours to 2 1/2 months), suggesting various pathological changes in functional state of the brain cortex induced by disturbances in neurological interrelationships.

[Morphofunctional evaluation of the condition of the brain in rats with different degrees of recovery of neurological status following arrest of systemic blood circulation].

The brain status was studied for four days after resuscitation of rats with different degrees of recovery of the neurological status after systemic circulatory arrest induced by the occlusion of vascular bundles of the heart. Morphometric analysis of the population of Purkinje cells from the two different functional zones of the cerebellum revealed that in comparison with completely recovered rats, the animals with disturbed neurological status were characterized by loss of neurons, disturbed composition of the neuronal population, development of severe dystrophic cell changes. The lateral zone of the cerebellum hemisphere was most affected.