[The action of corticosterone on the macroerg pool and membrane permeability in rat hippocampal slices during hypoxia]. / Deistvie kortikosterona na pul makroérgov i sostoianie membrannoi pronitsaemosti v srezakh gippokampa krys pri gipoksii.

Incubation of rat hippocampal slices for 30 min in medium containing 900, 700, or 500 microM of O2 did not significantly change ATP, ADP, or CP levels, but when O2 content dropped to 100-200 microM the levels of ATP and CP decreased by 2 to 5 times. Under the same conditions CPK maximal solubilization was shown. Corticosterone acetate (CSA, 160 microM) did not show a membranotropic effect, nor did it influence the macroerg pool under conditions of high O2 content, but when O2 concentration was 100 microM a twofold increase of ATP and CP levels was observed. This effect correlated with a twofold increase of CPK membrane permeability. The results of this study permit us consider that membrane labilization is not a reflection of CSA neurotoxic effect in hypoxia. A relationship between CSA antihypoxic effect and macroerg pool increase is discussed.

[Changes in the level of cyclic nucleotides in the left and right sensorimotor areas of the cerebral cortex in rats after corazol-induced kindling]. / Izmeneniia urovenia tsiklicheskikh nukleotidov v levoi i pravoi sensomotornoi oblasti kory mozga krys posle korazolovogo kindlinga.

Levels of cAMP and cGMP in the left and right areas of the rat sensorimotor cortex (SMC) 7 days after pentylenetetrazole kindling (30 days) were determined by radioimmunological assay. It is shown that levels of cyclic nucleotides remained unchanged in rats SMC 7 days after single injection of seizure dose (70 mg/kg) of pentylenetetrazole. Levels of cAMP and cGMP in SMC increased by 2-3 times after 30-day administration of physiological saline as compared to single injection; cortical asymmetry of cAMP and cGMP is absent. Differences in the levels of cyclic nucleotides in sensitive and low-sensitive animals to pentylenetetrazole were not revealed. When kindling was completed cGMP level increased in right SMC and it decreased in left SMC as compared to control animals; cAMP level was unaltered in left and increased in right SMC. The role of cortical asymmetry of cyclic nucleotides development of seizure state is discussed.

[Differences in the hormonal status of rats highly and poorly resistant to hypoxia]. / Razlichiia gormonal'nogo statusa u vysoko- i nizkoustoichivykh k gipoksii krys.

Rats were tested for hypobaric hypoxia and decapitated two weeks later at 9-12, 13-14 and 15-17 o'clock. The levels of corticosterone, insulin and testosterone were determined in serum by RIA. Great daily fluctuations and higher elevation of corticosterone level in response to additional 1.5-min hypoxia were observed in low hypoxia-resistant (HHR) rats. The correlation of corticosterone/insulin ratio was directly proportional in LHR rats and inversely proportional in HHR rats. No difference in testosterone and insulin levels in LHR and HHR rats was found.

[The ACTH and cortisol content of the blood in experimental focal epilepsy]. / Soderzhanie AKTG i kortizola v krovi pri éksperimental'noi ochagovoi épilepsii.

In experiments on 87 freely behaving rats and 7 cats treated with d-tubocurarine and anesthetized with nembutal it was established that the generation of focus of epileptic activity (EA) in cerebral cortex by surface application of sodium benzylpenicillin is accompanied by an increase in the plasma level of ACTH (2-fold in rats and 2.5-fold in cats) with consequent rise in the plasma cortisol level (1.5-fold both in rats and cats). In cats a "delayed" rise in plasma ACTH was observed after the cessation of cortical EA. The described changes in plasma ACTH are a result of the pathological hyperactivity of neurons rather then a stressor component under the EA.