Effect of semax heptapeptide on the human electroencephalogram

The effect of the new regulatory peptide Semax (ACTH_4–10 fragment) on the electroencephalogram of a healthy person was studied. Semax was administered at 0.5 mg/kg intranasally in 9 volunteers without causing any nervous system pathology. The control group comprised 6 examinees treated in the same way with distilled water. The effect of Semax manifested itself on the electroencephalogram as a boost of biopotential strength in all ranges but especially in that of the α-rhythm, the zonal differences of which were enhanced, without any pathological signs being evident. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 1, pp. 116–117, January, 1996 Presented by I. P. Ashmarin, Member of the Russian Academy of Medical Sciences     

Antioxidant defense and lipid peroxidation in rat tissue after hypobaric hypoxia

Posthypoxic period is characterized by increased formation of lipid peroxidation products. Changes in the antioxidant enzyme systems include decreased catalase and glutathione reductase activities and elevated content of reduced glutathione. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 11, pp. 519–521, November, 1998     

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     

Effect of semax and semax-heparin mixture on isolated heart activity after total ischemia in rats

Semax administered after 40-min total ischemia of isolated heart improved the recovery of heart rate and reduced myocardial contracture. When administered prior to ischemia, Semax exerted a negative effect on recovery of heart contractility. Semax-heparin mixture significantly improved the recovery of cardiac indices (end-diastolic pressure, heart rate, and relaxation rate) irrespective of administration schedule. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 11, pp. 494–496, November, 1999     

Behavioral peculiarities and reactions of brain dopaminergic systems in rats with different resistance to acute hypobaric hypoxia

Locomotor activity in the open field test did not correlate with rat resistance to acute hypobaric hypoxia; there was a correlation between this resistance and rat behavior during acute stress. Immobility was characteristic of rats with low and particularly medium resistance to hypoxia; this reaction can be abolished by antidepressants. By contrast, highly resistant rats were mainly hyperactive. The resistance to hypoxia was associated with extreme parameters of dopaminergic neuron functioning. In low-resistant rats locomotor stereotypia was maximal, while perioral stereotypia was the minimal; highly resistant rats were characterized by an opposite pattern, and medium-resistant rats occupied an intermediate position. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 9, pp. 275–278, September, 2000     

Effect of adaptation to high-altitude hypoxia in early ontogeny on higher nervous activity

Newborn male and female Wistar rats were adapted to hypoxia in a pressure chamber. Adaptation began at an altitude of 1000 m for 1 h daily, after which the duration and intensity of exposure were gradually increased so that, starting from the 17th day, the animals were adapted to an altitude of 5000 m for 5 h on 5 days a week. After adaptation for two months, a conditioned active avoidance reflex was produced in the animals. In the adapted males a tendency was observed for the reflex to be formed more rapidly and for it to be preserved to a much greater degree than in the control animals. In females adapted to hypoxia under similar conditions no changes were observed in the formation and preservation of the reflex.Laboratory of Pathophysiology of the Heart, Institute of General Pathology and Pathophysiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 8, pp. 902–903, August, 1976.     

Effect of acute hypoxia in the antenatal period on functions of the higher levels of the CNS in rats

A decrease in motor activity, depression of the orienting reflex, and its faster extinction than in control animals were observed in sexually mature rats exposed to acute hypoxia in the antenatal period. Disturbances of conditioned reflex activity indicating impairment of fixation of the temporary connection, weakening of inhibition, and lowering of the mobility of nervous processes were discovered in the experimental rats. When tests involving difficult tasks were presented the experimental rats developed epiliptiform seizures. An increase in predisposition to seizures also was observed after administration of threshold doses of metrazol.Radiology Group, Moscow Research Institute of Psychiatry, Ministry of Health of the RSFSR. Laboratory of Neurochemical Mechanisms of the Conditioned Reflex, Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR E. V. Shmidt.) Translated from Byulletin' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 8, pp. 928–930, August, 1976.     

Effect of semax on homeostasis of gastric mucosa in albino rats

The ACTH_4–7 analogue Semax administered intrapeitoneally in a dose of 50 μg/kg 1 h before exposure to ulcerogenic factors (ethanol, water immersion immobilization stress) protected gastric mucosa from damage. Postoperative treatment with Semax for 5 days after application of glacial acetic acid on the mucosa prevented acetic acid-induced ulcers and promoted their healing. The antiulcer effects of Semax in the studied dose were comparable with those of tripeptide Pro-Gly-Pro in a dose of 1 mg/kg. Translated fromByulleten “Eksperimental'noi Biologii i Meditsniy, Vol. 130, No. 9, pp. 300–302, September, 2000     

Effect of insulin and adrenocorticotropic hormone on rat brain cortex in the early postnatal period

Administration of insulin and adrenocorticotropic hormone to 1-, 2-, and 3-day-old rats leads to an increase in the RNA and total protein contents of cortical neurons, while administration of adrenocorticotropic hormone alone increases the number of dying neurons in layer V of the cortex. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 9, pp. 305–307, September, 1995 Presented by V. A. Trufakin, Member of the Russian Academy of Medical Sciences     

Effect of acute hypobaric hypoxia on spermatogenesis and lactate concentration in testicular tissue of male albino rats

Parameters of spermatogenesis in male albino rats was studied after experimental acute hypobaric hypoxia. The number of spermatogenic epithelial cells, Sertoli cells, and Leydig cells in testicular tissue significantly decreased in the posthypoxic period. Single exposure to hypoxia led to significant changes in lactate concentration in the testicular tissue. Cell composition of the testicles did not return to normal by the 60th day after treatment. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 1, pp. 24–26, January, 2006     

Effect of trimetazidine on cerebral metabolism during acute ischemia complicated by hypoxia

In experiments on rats, trimetazidine (25 mg/kg) prevented disturbances in energy metabolism and LPO activation in the brain under conditions of acute ischemia aggravated by hypoxia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 2 pp. 142–144, February, 2000     

Protective effects of trimetazidine in acute hypoxia

Trimetazidine improves resistance to acute hypobaric hypoxia. Intraperitoneal injection of this preparation in an optimal protective dose (25 mg/kg) to rats prevents serious disturbances of energy metabolism and activation of lipid peroxidation in the brain, heart, and liver. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 4, pp. 410–412, April, 1998     

Effects of regulatory peptides on changes in the content of brain stem catecholamine in rats during hypoxia and hemorrhage

Effects of regulatory peptides FMRFa, thyroliberin, and Semax (ACTH_4–10 analogue) on changes in the content of biogenic amines in rat brain stem observed 1 and 20 min after termination of hypoxia and 5 min after bloodletting (hemorrhage) were studied. The content of norepinephrine decreased to 82% of the control level 20 min after hypobaric hypoxia, while preliminary administration of the peptide complex abolished this effect. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 11, pp. 518–520, November, 1999     

Effect of melatonin on the relationship between lipid peroxidation and proteolytic activity in basal nuclei of rat brain during acute hypoxia

We studied the effect of melatonin on the relationship between LPO intensity and proteolytic activity in basal nuclei (caudate nucleus, globus pallidus, amygdaloid complex, and nucleus accumbens septi) of rat brain during acute hypobaric hypoxia. Acute hypoxia was accompanied by LPO activation and increase in proteolytic activity. It should be emphasized that the intensity of proteolysis was higher in structures responding by more pronounced LPO activation (nucleus accumbens septi and globus pallidus). Intraperitoneal injection of 1 mg/kg melatonin 30 min before acute hypoxia inhibited LPO and prevented the increase in proteolysis in basal nuclei of the brain. The effect of melatonin was most pronounced in basal nuclei highly sensitive to acute hypoxia. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 142, No. 7, pp. 94–96, July, 2006     

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.     

Changes in hemodynamics and respiration in animals with different resistance to acute hypoxia

We studied the effects of acute hypoxia on hemodynamics and respiration in cats. The animals were divided into high-, low- and medium-resistant to hypoxia by the time of respiratory arrest after breathing with 3% O₂ gas mixture. In high-resistant animals, hemodynamic indices remained at a high level throughout the hypoxic episode, while in low-resistant cats they decreased shortly after the onset of hypoxia. It is suggested that the peculiarities of hemodynamic regulation play an important role in individual resistance to acute hypoxia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 9, pp. 286–290, September, 1999     

Effect of cold stress in early postnatal ontogeny on blood pressure and heart activity in normo- and hypertensive rats

Cold stress in the early postnatal ontogeny caused permanent functional changes in the cardiovascular system, which were different in hypertensive NISAG and normotensive WAG rats. Stress led to elevation of blood pressure and overload on the left heart chambers in adult WAG rats postnatally exposed to cold. At the same time, postnatal exposure to cold stress attenuated functional disturbances typical of hypertensive NISAG rats. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 12, pp. 660–664, December, 2000     

Effect of hypoxia of increasing severity on the dynamics of cerebral cortex EEGs in rats with different resistance to acute oxygen deficiency

EEGs recorded from the cerebral cortex of rats with high and low resistance to hypoxia during “elevation” in a pressure chamber differ in the dynamics of the EEG power spectra. EEGs of highly resistant rats show phasic changes in biopotentials correlating with the severity of hypoxia: primary increase in the absolute power of all frequency ranges is followed by normalization and a secondary increase with predominance of the slow-wave component, inhibition of the β₂ range and the emergence of interhemispheric differences, and terminal inhibition of the power of all frequency ranges. In rats with low resistance to hypoxia, phases of relative normalization of EEG spectra and their depression during terminal period are not observed, all changes being represented by a continuous increase in the power of the α and δ ranges with progressive inhibition of the β₂ range and then of the β₁ range. Interhemispheric asymmetry is significant throughout the period of power increase. A high amplitude burst activity is recorded in rats of both types starting from an altitude of 8000 or 9000 m. The pattern of EEG changes in rats exposed to hypoxia of growing severity consistently reproduces those observed in patients with ischemic stroke. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 9, pp. 262–267, September, 1996     

Effect of melatonin on cyclic nucleotide content and intensity of lipid peroxidation in the hippocampus and habenula of rats exposed to acute hypoxia

Single intraperitoneal injection of melatonin in a dose of 1 mg/kg prevented accumulation of cGMP and intensification of lipid peroxidation in the hippocampus and habenula of rats exposed to acute hypobaric hypoxia (12,000 m). Changes in habenular content of cGMP suggest that melatonin prevents hypoxia-induced activation of heme-oxygenase. Translated fromByulleten' Eksperimental" noi Biologii i Meditsiny, Vol. 130, No. 8, pp. 168–171, August, 2000     

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