[Conditioning in resuscitated rats with originally different behavioral patterns].

Male white rats divided in three groups on the basis of their behavior in the elevated plus-maze were subjected to 10-min cardiac arrest. Analysis of the results of their subsequent food and active avoidance conditioning revealed the effects of the following factors: (1) a factor of initial typological features of the higher nervous activity, (2) a factor of general brain mechanisms of postresuscitation, and (3) a factor of postresuscitation features in rats with different behaviors, which represented changes in different mechanisms of conditioned reflex performance in these animals.

[Postresuscitation cerebral structural and functional changes associated with the initial type of behavior]. / Postreamanitsionnye strukturno-funktsional'nye izmeneniia mozga, sopriazhennye s iskhodnym tipom povedeniia.

The elevated cross-shaped labyrinth test carried out on highly, moderately, and low active experimental animals revealed significant differences in the baseline density and composition of neuroglial populations of numerous formations of the brain, as well as in the early structural and functional sequels of experienced clinical death. The most pronounced postresuscitation abnormal changes were observed in highly active animals and the least marked ones were seen in moderately active animals.

[Effect of perftoran on post-resuscitation recovery of the central nervous system]. / Vliianie perftorana na postreanimatsionnoe vosstanovlenie tsentral'noi nervnoi sistemy.

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. Perfluorane activated behavioral reactions and prevented development of dystrophic changes in the brain structures of rats highly sensitive to hypoxia.

[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]. / Otsrochennye éffekty ostanovki sistemnogo krovoobrashcheniia na svobodnoradikal'nye protsessy v strukturakh mozga krys s raznymi tipami povedeniia v teste émotsional'nogo rezonansa.

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. A decrease in superoxide scavenging activity and in the content of 2-thiobarbituric acid-reactive material was revealed in the cerebral structures of both "active" and "passive" rats. Increased levels of free-radical generation in the hippocampus of the "passive" rats and in the cerebellum of the "active" rats were found. Higher NO-synthase activity was demonstrated in the cerebellum of the "passive" rats. Taken together, these data suggest that there are specific patterns of free-radical-mediated processes in the brain of rats with different types of behavior in "emotional resonance" test.

[Post-resuscitation neurosomatic deviations and the feasibility of their correction with a drug of metabolic action]. / Postreanimatsionnye neirosomaticheskie otkloneniia i vozmozhnosti ikh korrektsii preparatom metabolicheskogo deistviia.

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. after restoration of effective cardiac activity and the next 3 days. Proxipin improved resuscitation outcomes, relieved symptoms of CNS excitability 4-6 months after resuscitation, changed adaptation to stress agents, protected against risk-factors of atherogenesis. However, proxipin-induced inhibition of the motor activity suppressed the free-choice ability to find food.

[Effects of active behavior in the postresuscitation period on the functional and morphological characteristics of the brain]. / Vliianie aktivizatsii povedeniia v postreanimatsionnom periode na funktsional'nye i morfologicheskie kharakteristiki mozga.

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. These results support the hypothesis proposed by A. M. Gurvich on the possibility of regulating the postresuscitation recovery of the central nervous system by neurophysiological treatment of the brain.

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. / Vliianie sistemnoi ostanovki krovoobrashcheniia na protsessy svobodnoradikal'nogo okisleniia i aktivnost' NO-sintazy v strukturakh mozga krys s razlichnymi tipami povedeniia v teste émotsional'nogo rezonansa: ostrye éffekty.

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. The majority of behavior-related biochemical differences were induced by cardiac arrest. These differences could be global or related to specific brain structures. Sometimes they became apparent in cerebral lateralization of biochemical indices.

[The effect of succinic acid on postresuscitation pathology of the CNS and of the body as a whole]. / Vliianie iantarnoi kisloty na postreanimatsionnuiu patologiiu TsNS i organizma v tselom.

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. In addition, succinic acid prevented the development of risk factors of atherogenesis, namely, increase of the levels of blood cholesterol, triglycerides, and low and very low density lipoproteins. Further studies are needed to validate the addition of succinic acid to the armory of drugs preventing the development of postresuscitation encephalopathies in remote (3 months) periods.

[Effects of sodium succinate on functional, biochemical and morphological indicators of CNS repair in rats after 10-minute circulation arrest]. / Vliianie suktsinata natriia na funktsional'nye, biokhimicheskie i morfologicheskie pokazateli vosstanovleniia TsNS u krys posle 10-minutnoi ostanovki krovoobrashcheniia.

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. The second series of experiments was devoted to therapeutic effect of sodium succinate in the same dose injected from day 3 to day 7 after revival on the orientation and investigation behaviour in an "open field" test, on changes in radical formation in the blood serum and the brain, and on the cholesterol/lipid ratio in the brain, as well as on the morphologic changes in the cerebral hemispheres and the cerebellum. In contrast to untreated animals, the treated ones had a less intensive reaction in the "open field" test in response to acute stressor exposure, their cerebral and blood serum levels of free radical processes were reduced, the destruction of neuronal membranous elements was less intensive, as were dystrophic changes in the cerebral cortex and the cerebellum. The data permit a conclusion about antistressor and protective effect of sodium succinate in the postresuscitation period at the functional, biochemical, and morphological levels.

[Delayed postresuscitation degenerative changes in the brain and ways of studying their pathogenesis]. / Otsrochennye postreanimatsionnye degenerativnye izmeneniia v mozge i nekotorye puti issledovaniia ikh patogeneza.

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. These changes reflect the development of postresuscitation disease and may become the cause of delayed encephalopathies. The problem of the possible mechanisms of development of progressive postresuscitation degeneration of the central nervous system and approaches to studies there of is discussed.

[Effect of the tranquilizer gidazepam on the behavioral reactions of rats in the first weeks after resuscitation]. / Vliianie trankvilizatora gidazepama na povedencheskie reaktsii krys v pervye nedeli posle reanimatsii.

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.p.) produced a sedative effect in the first week after resuscitation, then 6-8 weeks later it displayed its anxiolytic and activating effect which is similar to this dose of the agent given to intact animals. The findings suggest that there are changes in the pattern of neurophysiological abnormalities, as well as a response of the benzodiazepine receptor complex to drugs during a resuscitative process, which may be one of the components of formation of a post-resuscitative central nervous abnormality.

[Regional perfusion and oxygenation in the early resuscitation period following prolonged clinical death]. / Regionarnaia perfuziia i oksigenatsiia v rannem postreanimatsionnom periode posle dlitel'noi klinicheskoi smerti.

Cardiac output distribution and oxygen supply in the period starting from 15 min after resuscitation to 7 h were studied in 23 dogs exposed to 10 min clinical death caused by blood loss. The ratio of supra- to subdiaphragmatic bloodstream was virtually unchanged. Redistribution of the flow in favor of hind limb muscles was observed in the subdiaphragmatic region only between the 15th and 30th minutes. Reduction of oxygen transport during prolonged hypoperfusion (2-6 h) was associated with increased oxygen utilization in all areas which was expressed most of all in the supra-diaphragmatic region and in limb tissues and the least so in the splanchnic area, with oxygen consumption remaining at the initial level or surpassing it. A close relationship was revealed between oxygen transport and consumption in the supradiaphragmatic sector and posterior limb tissues combined with critical levels of pO2 and HbO2 in outflowing blood. Stably surviving animals differed from those dead in 1 sec by a lesser depression of the bloodstream and oxygen transport in the body on the whole and in the supradiaphragmatic region, a lesser oxygen consumption by the supradiaphragmatic region at the 15th-30th minutes, and a higher O2 consumption in 3-6 h under conditions of more marked spontaneous hypothermia.

[The characteristics of the adaptive behavior, neurological recovery and a morphometric analysis of the cerebral cortex in rats in the postresuscitation period]. / Osobennosti adaptivnogo povedeniia, nevrologicheskoe vosstanovlenie i morfometricheskii analiz kory mozga krys v postreanimatsionnom periode.

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. Morphometric studies have revealed changes in neuroglial relations by day 14 and considerable dystrophic neuronal changes by month 1 after resuscitation. All these disturbances took place with the overall density of neuron population preserved.

[Role of initial hemodynamic status and rate of blood loss replacement in postresuscitation changes in blood circulation and animal mortality]. / Rol' iskhodnogo gemodinamicheskogo statusa i tempov vozmeshcheniia krovopoteri v postreanimatsionnykh izmeneniiakh krovoobrashcheniia i gibeli zhivotnykh.

In 43 experiments performed on narcotized dogs after 10 min clinical death induced by exsanguination, the peculiarities of postresuscitation changes in the blood circulation associated with the initial hemodynamic status, the rate of the blood loss replacements after restoration of cardiac activity, and the use of infusion therapy by albosorb (specifically processed albumin) were studied. The effect of the initial level of stroke index (SI) on the pronouncement of postresuscitation derangements in the central hemodynamics (CHD) and on the resuscitation outcome was determined. With the initial value of SI being mean, the maintenance of a moderate blood deficit (10 to 15 ml/kg) within the first hour of restoration was accompanied by an improvement in the survival rate of the animals as compared with a rapid and complete replacement of the blood. The infusion of albumin and creation of a moderate overtransfusion by the first hour post resuscitation removed the prognostic value of the initial SI.

[Dynamics of the cerebrospinal fluid and elastic properties of the cerebrospinal system (a bolus technic)]. / Likvordinamika i uprugie svoistva tserebrospinal'noi sistemy (boliusnaia tekhnika).

The theoretical aspects of employing the infusion methods of examination of CSF time course and viscoresilient properties of the cerebrospinal system (CSS) are discussed. The general formula of changes in the time of intracranial pressure (TIP) after a load is given. Dog experiments showed this formula to reflect sufficiently exactly the behavior of the CSS in a TIP range of 24 to 40 cm H2O. Analysis of the data in the literature and the results of the author's studies allows the conclusion that determination of CSF resorption resistance by the method of infusion under constant pressure with subsequent calculation of the CSS resilience gradient from the curve of TIP reduction makes it possible to avoid the disadvantages of the bolus technique.

[Evaluation of blood flow heterogeneity in the limbs of dogs by hydrogen clearance in venous blood]. / Ob otsenke neodnorodnosti krovotoka v konechnosti u sobak po klirensu vodoroda v venoznoi krovi.

On the basis of Fick's principle, concept of the tissue blood flow heterogeneity and H2 concentration changes in arterial blood after short-term hydrogen inhalation, a method of calculating some blood flow indices in the limbs by H2 content desaturation changes in venous blood was developed. The suggested method allows to calculate the mean regional flow rate, its compartmentation, and blood flow/tissue volume ratio for the measured components of the regional blood flow. In the limb tissue of anesthetized dogs, two components of the blood flow with the rates 0.79 +/- 0.07 and 0.12 +/- 0.01 were measured, their mean rate being 0.16 +/- 0.01 ml/min. g. The share of the "slow" component in total blood flow and tissue volume was 70 +/- 3 and 93 +/- 1 per cent respectively.

[Role of certain brain structures in the generation and spread of alpha-like activity in dogs peculiar to the early stages of the postresuscitation period]. / Rol' nekotorykh obrazovaii golovnogo mozga v generatsii i rasprostranenii alpha-podobnoi aktivnosti u sobak, svoistvennoi rannim étapam postreanimatsionnogo perioda.

The role played by the amygdaloid nucleus, caudate nucleus, thalamus and brain cortex in propagation throughout the brain of generalized limbic alpha-like activity recorded on the EEG in the early postresuscitation period was studied in experiments on dogs resuscitated after a 13-15-minute circulatory arrest. Destruction or pharmacological inhibition of both amygdaloid nuclei resulted in disappearance of alpha-like activity from all the test structures. Coherent analysis showed that the caudate nucleus and thalamus, in particular, take an active part in propagation of alpha-like waves of biopotentials from the amygdaloid nucleus to other brain structures.