Impaired plasticity of hippocampal synaptic transmission in rats exposed to prenatal hypoxia is normalized by treatment with nootropic dipeptides

Experiments on hippocampal slices from young rats exposed to hypobaric hypoxia duringin utero development revealed enhanced responsiveness (an increase in a CA1 field response amplitude) and reduced plasticity (a low incidence of field response long-term potentation following high-frequency stimulation) of CA1 pyramidal neurons. Postnatal treatment of animals with piracetam peptide analogs constructed on the basis of pyroglutamate and proline normalized both these physiological indices. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 12, pp. 592–595, December, 1995 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

New endogenous dipeptide cycloprolyl-glycine is similar to piracetam by its mnemotropic selectivity

The effects of endogenous dipeptide cycloprolyl-glycine on learning and memory in the model of postconvulsive retrograde amnesia of passive avoidance response in rats depended on the administration schedule. The dipeptide prevented retrograde amnesia, when injected prior to learning, had no effect after postlearning administration, and aggravated amnesia, when injected immediately before retrieval. These data suggest that cycloprolyl-glycine is similar to the standard nootropic piracetam by its mnemotropic activity. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol.128, No. 10, pp. 411–413, October, 1999     

Effect of acute hypoxia on resistance to hypoxia in rats

The resistance of rats to hypoxia was measured by survival time after exposure to high-altitude (11.5 km) hypoxia. The first exposure to acute hypoxia caused phasic changes in the survival time: short-term in high-resistant rats (about 24 h) and long-term in moderate- and lowresistant rats (38–39 days) starting from 1 h and 6–7 days after the first exposure, respectively. Adaptive reactions were more pronounced in low- and moderate-resistant rats, while disadaptation was typical of high-resistant animals. In all rats, the adaptive effect dominated until days 22–23. Throughout the testing, the initial type of resistance was retained in 79% of high-resistant rats, in 41% of low-resistant and in 33% of moderate-resistant rats, i. e., the initially homogenous groups formed after the first exposure in accordance with the type of resistance became mixed, which reduced the intergroup differences. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 6, pp. 625–628, June, 1999     

Sustained aftereffect of the amnestic action of scopolamine in rats and its elimination by piracetam

Experiments were carried out on male Wistar rats to assess (1) the effect of chronically administered (for 20 days) scopolamine on their learning capacity and memory 10 days after its last administration and (2) the influence of the nootropic piracetam, given for 10 days after scopolamine and before learning a conditioned passive avoidance response, on cognitive functions of the brain altered as a result of the M-cholinergic receptors being blocked by scopolamine. Scopolamine-dosed rats showed poor reproduction of the conditioned passive avoidance response when tested for this response at 24 h and 30 days after learning it, whereas those treated with piracetam after scopolamine retained the response well both at 24 h and at 30 days. Piracetam also restored the scopolamine-impaired acute extinction of orienting/exploratory activity in the rats. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 4, pp. 372–374, April, 1995 Presented by S. B. Seredenin, Member of the Russian Academy of Medical Sciences     

Effect of low doses of piracetam on conditioned-response memory in rats

Effects of low doses of piracetam, a psychotropic nootropic, on the memory of rats are studied. A positive effect of the drug in a dose many times lower than the doses used routinely is demonstrated on a model of elaboration of the active avoidance reaction. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 7, pp. 60–61, July, 1995 Presented by I. P. Ashmarin, Member of the Russian Academy of Medical Sciences     

Changes in the mesenteric microcirculation of rats with acute hypoxic hypoxia

Hypoxia was induced in rats by administration of a gas mixture corresponding to the composition of the atmosphere at an altitude of 6000 m above sea level. Mesenteric arteries and veins measuring from 9 to 43 in diameter were studied. Their diameter and the pressure and velocity of the blood flow in them were measured. The arterial microvessels were dilated in hypoxia. Their diameter was increased by the greatest amount (by 3–5 ) during the first 3–5 min of administration of the gas mixture. The blood pressure and velocity of blood flow in these vessels were reduced throughout the experiment.Department of Normal Physiology, Abu Ali ibn-Sina Tadjik Medical Institute, Dushanbe. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 3, pp. 277–279, March, 1976.     

Effect of piracetam administration to suckling rats on morphometry of neocortex and hippocamp

The frontoparietal and parietal lobes of neocortex and hippocamp were studied in one-month-old rats, which were daily given piracetam 1000 mg/kg i.p., starting from the 5th day of life. In piracetam-treated animals, an increase in the thickness of cortex in frontoparietal lobe and of the size of neuronal nuclei both in layer V of parietal and frontoparietal lobes of neocortex, and in zones CA1-CA5 in hippocamp were observed. RNA concentration increased in neuronal cytoplasm in layer V of neocortex and in hippocamp. The brain mass, the density of neurons in the neocortex (layers II and V), the cortical thickness of neocortex in the parietal lobe did not differ in the control and experimental groups. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 8, pp. 154–156, August, 1997     

Changes in hypoxia resistance in rats during daytime

The resistance to acute hypoxia in male Wistar rats was evaluated by the period of survival after exposure to high-altitude hypoxia (11.5 km above see level). The study was performed during daytime (13.00–21.00) in autumn. The fatal rat population was characterized by the log-normal distribution of survival periods. The rats with low and moderate resistance to hypoxia exhibited similar diurnal variations in it with gradual decrease by the end of daytime more pronounced in low-resistant rats. The rats with high resistance showed relatively constant resistance to hypoxia which decreased only at 21:00. All groups revealed a relatively stable resistance to hypoxia from 16:00 to 18:00. These variations in the resistance to hypoxia should be taken into consideration when planning experimental research. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 3, pp. 256–260, March 1999     

Effect of amiridin and piracetam on memory disturbances induced by experimental stress

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 115, N ^o 2, pp. 155–157, February, 1993.     

Phospholipid metabolism in microsomes and cytosol of brain tissue of normal rats and rats with hypoxic hypoxia

The content and intensity of metabolism of phosphate groups of various phospholipids (phosphatidylcholines, monophophoinositides, aminophospholipids) were studied in homogenate, microsomes, and cytosol of the rat brain under normal conditions and in hypoxic hypoxia (240 mm Hg). The concentration of phospholipids per milligram protein was found to be highest in the microsomes and lowest in the cytosol, but the total phospholipids of the cytosol had the highest metabolic rate of their free phosphate groups. Hypoxia, while not affecting the phospholipid concentration, depressed the intensity of their metabolism; this depression of metabolism, moreover, was about equal in all the tissue preparations studied.Laboratory of Regulation of Brain Metabolism, I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Chernigovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 11, pp. 533–535, November, 1978.     

Ultrastructural reorganization of adrenal cortex in rats exposed to hypoxia and treated with nandrolone

Single and repeated hypoxic exposures induced different ultrastructural changes of varying intensity in adrenocorticocytes of rat adrenal zona fasciculata and zona reticularis. Destructive changes in cells were caused by the antianabolic effect of hypoxia and inhibition of regeneration and plastic processes. Treatment with nandrolone (Nerobolil, Gedeon Richter) diminished this effect and stimulated secretory activity of adrenocorticocytes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 5, pp. 588–592, May, 1999     

Adaptation to periodic hypoxia restricts subdural hemorrhage during audiogenic epileptic seizures in rats

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 116, N ^o 12, pp. 572–574, December, 1993     

Pharmacokinetics of antipyrine in rats with different resistance to hypoxia in cold stress

It is shown that the parameters of antipyrine pharmacokinetics during cold exposure depend on individual resistance to hypoxia. High-resistant rats are characterized by less intense metabolism and more rapid normalization of pharmacokinetic parameters than lowresistant rats characterized by shortened elimination half-time corresponding to a more rapid metabolism of xenobiotics under conditions of cold stress. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 11, pp. 513–515, November, 1998     

Protective effect of adaptation to hypoxia and its prolongation by pharmacological agents in rats prone to audiogenic epilepsy

Cytophotometric determination of RNA in various brain structures of hypoxia-adapted and unadapted epilepsy-prone rats at different times after an epileptic seizure shows much smaller decreases in RNA levels and their much more rapid return to normal in the adapted than in the unadapted rats. The adaptation to hypoxia produces a marked anticonvulsive effect, and this effect is enhanced and prolonged considerably by pharmacotherapy. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 2, pp. 120–123, February, 1994     

Effect of semax heptapeptide on rat heart activity during acute hypobaric hypoxia in the early postnatal period

The effects of Semax heptapeptide on the resistance to acute hypobaric hypoxia and on hypoxic changes in the ECG chronotropic index were studied in 14- and 21-day-old pups. The resistance to hypoxia decreased with age. Hypoxic exposure caused bradycardia in both age groups. Semax reduced the bradycardiac reaction and exerted an antiarrhythmic effect without affecting the resistance to hypoxia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 8, pp. 161–164, August, 1999     

Activity of liver monooxygenase system in rats with low and high resistance to hypoxia

Rats with low and high resistance to hypoxia are shown to differ in terms of the baseline activity of liver monooxygenases bothin vivo andin vitro. Low-resistance animals are characterized by a significantly higher rate of elimination of antipyrine, hexenal, and nifedipine, as evidenced by shorter half-elimination period and higher urinary concentration of metabolites. The concentration of microsomal cytochromes P-450 and b5 as well as the rates of N-demethylation of amidopyrine, p-hydroxylation of aniline, and hydroxylation of diazepam are considerably higher in rats with low resistance to hypoxia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 9, pp. 291–294, September, 1996     

Biotransformation of hepatic xenobiotics in rats with various resistance to hypoxia exposure to after cold

Hepatic monooxygenase activity was studied in rats with various resistance to hypoxia during adaptation to cold. Cold-induced change in the concentrations of cytochromes P-450 and b₅ and the activity of microsomals metabolism of amidopyrine and aniline were shown to be associated with individual resistance to hypoxia. The content of microsomal cytochromes in highly resistant rats did not change on the fifth day of cold exposure. However, the intensity of metabolic reactions decreased. In low-resistance rats, a cold-induced decrease in the concentration of the cytochromes was not accompanied by significant changes in metabolic rates of amidopyrine and aniline. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 12, pp. 631–633, December, 1998