The effect of etimyzol on the development of the deafferentation pain syndrome

Administration of etimyzol in a dose of 4 mg/kg to rats with deafferentation pain syndrome reduces the incidence of the syndrome and its severity. This effect is associated with activation of the hypothalamic-hypophyseal-adrenal system. Systematic administration of the preparation models repeated stress, thus developing adaptation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 3 pp. 258–261, March, 1996 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

On the involvement of endogenous μ- and δ-opiate receptor agonists in the antiarrhythmic effect of adaptation

Rats adapted to stress showed a decreased severity and incidence of cardiac arrhythmias induced by epinephrine, and these effects of adaptation were abolished by naloxone. It is suggested that stress adaptation mitigates arrhythmia by activating the endogenous opioid system and stimulating the μ-opiate receptors. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 1, pp. 24–25, January, 1996 Presented by R. S. Karpov, Member of the Russian Academy of Medical Sciences     

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     

Adaptation to periodic hypoxia and a diet supplemented with polyunsaturated class ω-3 fatty acids enhance the resistance of Ca2+ transport in the myocardial sarcoplasmic reticulum to free-radical oxidation

The relationship between the level of accumulation of lipid peroxidation products and the status of the Ca²⁺-transporting system in the sarcoplasmic reticulum of the rat myocardium is studied against the background of two cardioprotective factors, namely adaptation to periodic hypoxia and a diet enriched in polyunsaturated fatty acids of the ω-3 class. It is shown that the diet leads to an increase of level of lipid peroxidation products by 1.8 times in the heart and by 19 times in the liver, whereas a adaptation has no effect on the level of lipid peroxidation products in either of these organs. At the same time, the combined action of both factors considerably enhances the resistance of the myocardial Ca²⁺-transporting system to free radical-induced oxidation. Inin vitro experiments it is shown that adaptation to periodic hypoxia results in a more than twofold deceleration of Ca²⁺ transport inhibition during the oxidation induction by the Fe²⁺/ascorbate system; the diet causes a 3.5-fold deceleration of such inhibition. The results show that the accumulation of a high level of lipid peroxidation products is not always followed by damage to the Ca²⁺-transporting system in the myocardial sarcoplasmic reticulum. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 7, pp. 42–45, July, 1995 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Expression of the c-myc and Ca-ATPase genes in cardiac muscle during adaptation to repeated stress

In the course of adaptation to repeated stress, the expression of the proto-oncogene c-myc found to increase much more rapidly than that of the Ca-ATPase gene. It is suggested that an increase in the level of c-myc expression may activate the structural Ca-ATPase gene and possibly also the heat-shock proteins. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 2, pp. 124–126, February, 1994     

Reactivity of the conjunctival microcirculatory bed in students from various regions of the world as an indicator of adaptation of the organism

Microcirculatory vessels of the eyeball conjunctiva were examined during exercise in students from Asia, Africa, and Latin America. The reactivity of microvessels was found to be increased at the early stages of adaptation, which indicates a high-level compensatory potential of the organism. An appreciable reduction of microvessel reactivity after 1 to 2 years of university studies indicates a decrease of the compensatory potential in this period of adaptation. After 4–5 years of studies the reactivity of the microvessels is virtually the same in foreign and Russian students, this indicating the formation of a stable phase of adaptation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 4, pp. 423–426, April, 1995 Presented by N. A. Agadzhanyan, Member of the Russian Academy of Medical Sciences     

Adaptation to hypoxia,unlike adaptation to stress,fails to protect the isolated heart from reperfusion after total ischemia (An NMR study)

Effects of adaptation to hypoxia on the contractility of isolated rat hearts and on their levels of ATP and inorganic phosphate after total ischemia were evaluated. This adaptation failed to render the cardiac energy-supplying system more resistant to postischemic reperfusion and thus did not accelerate the restoration of cardiac contractility after ischemia. The results of adaptation to hypoxia were then compared with those of adaptation to stress, which had been shown to bring about a marked increase in cardiac resistance to postischemic reperfusion. It is concluded that the profound differences noted between the cardioprotective effects of these two forms of adaptation are due to a much greater accumulation of stabilizing proteins from the HSP70 family during adaptation to stress. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 11, pp. 481–484, November, 1995 Presented by N. R. Paleev, Member of the Russian Academy of Medical Sciences     

Adaptation to multiple electrostimulation limits hemorrhages in the brain of rats with audiogenic epilepsy

Exposure of Krushinsky-Molodkina rats (a strain genetically predisposed to audiogenic epilepsy) to multiple electrostimulation (a course consisting of 10 sessions) prolongs the latency of epileptic seizures, lowers blood levels of stress hormones, lessens the severity of seizures, and reduces by half the area occupied by subdural hemorrhages. It is concluded that the major role in the mechanism of these protective effects is played by adaptation to stress, accompanied by the accumulation in the brain of heat-shock proteins that stabilize cellular structures. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 2, pp. 127–129, February, 1994     

Cellular composition of the lymphoid tissue of splenic structural components in mice during exercise

Experiments with BALB/c mice demonstrated that dosed exercise (swimming) induced changes at the organ and tissue level indicative of weakening of the immunity system. Changes in the cytoarchitectonics of various structural components of the spleen point to a more intensive development of the adaptation processes during vigorous exercise in comparison with moderate exercise Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 8, pp. 166–168, August, 1994 Presented by M. R. Sapin, Member of the Russian Academy of Medical Sciences     

Effects of adaptation to intermittent hypoxia on oxidative phosphorylation in brain mitochondria of rats with different sensitivities toward oxygen deficiency

After long-term adaptation to intermittent hypoxia, rats with an initially low resistance to acute oxygen deficiency were 2 to 4 times more resistant to it, while highly resistant rats did not show a significant change in resistance. The adaptation was accompanied by weakening of the electron-transporting function of the respiratory chain and increasing efficiency of oxidative phosphorylation in the brain mitochondria oxidizing NAD-dependent substrates, indicating that energy was produced in a more economical way. The succinate oxidase pathway of oxidation was found to be utilized to only a limited extent as a compensatory mechanism in animals exposed to intermittent hypoxia over a prolonged period. The effects of adaptation were more marked in the brain mitochondria of rats initially highly sensitive to oxygen deficiency. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 12, pp. 572–575, December, 1995     

Effect of various oxygen concentrations on the ATP content in isolated hepatocytes of rats adapted and nonadapted to hypoxia

It is shown that isolated hepatocytes are capable of perceiving slight changes in the envioronmental oxygen concentration. A complicated phase dependence exists between adenosine triphosphate and partial oxygen pressure, which differs in cells from animals with high and low resistance to hypoxia, the former showing a more stable and resistant energy-synthesizing function than the latter. After long-term adaptation to periodic hypoxia, the resistance of the energy-synthesizing function rises in hepatocytes from high-resistant animals, and falls in low-resistant animals suggesting a fundamentally different organization of the emergency compensatory mechanisms of the energy-synthesizing function in hepatocytes of animals of these two types. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 12, pp. 576–581, December, 1994     

Effect of dexamethasone on the expression of binding sites for high-density lipoproteins in cultured rat hepatocytes (Independence of the hormone effect on the intracellular cholesterol pool)

It is shown that glucocorticoids play a key regulatory role directed toward the maintenance of an optimal level of binding and internalization of HDL₃ in hepatocytes. Their stimulatory effect on the expression of HDL receptors proves to be independent of changes in the CH content in parenchymal cells. Translated fromByulleten' Eksperimentalnoi Biologii i Meditsiny, Vol. 117, N ^o 1, pp. 50–53, January, 1994     

Role of glycolysis in the maintenance of the energy-synthesizing function of hepatocytes from rats adapted and nonadapted to hypoxia at different oxygen concentrations

It is demonstrated that the lactate-Po₂ dependence is the same in hepatocytes of rats with high and low resistance to hypoxia and does not correlate with phasic changes in the ATP concentration in the 890–50 μM O₂ region. Strong activation of lactate formation against the background of ATP decrease indicates that glycolysis is not the major mechanism determining the steady-state ATP level in the cell and affecting the ATP-Po₂ relationship in a wide range of oxygen concentrations. The intensity of glycolysis in hepatocytes of rats with high resistance to hypoxia is markedly increased after periodic adaptation to hypoxia but remains practically unchanged in the hepatocytes of low-resistance rats. This indicates that fundamentally different compensatory mechanisms are involved in this process in the liver of high- and low-resistance rats. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 28–32, January, 1995     

Effects of adaptation to hypoxia on cytochrome levels in the brain and liver of rats

After a prolonged (for 30 days) adaptation of rats to intermittent hypoxia, their brains contained lowered levels of mitochondrial cytochromes, despite an increase in the number of mitochondria in the brain tissue mass, along with similar levels of high-energy compounds and more protein as compaired to the brains of unadapted controls. A mitochondrial population with novel properties presumably emerged in the brain. These effects were all more strongly marked in rats with an initially low resistance to hypoxia. In the liver of hypoxiaadapted animals, unlike in their brain, cytochrome levels in the mitochondrial and microsomal redox chains were lowered and the biogenesis of mitochondria was much less intensive. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 12, pp. 576–579, December, 1995     

Effect of some lectins on the cholinergic structures of the frog heart

The effect of lectins (phytohemagglutinin — PHA, concanavalin A — ConA,Pisum sativum lectin — PSL,Ricinus communis lectin — RCL, and pokeweed mitogen — PWM) on the cardiac cholinoceptors is studied in experiments on isolated hearts of maleRana temporaria frogs. The test lectins in concentrations from 10⁻²³ to 10⁻³ are shown to exhibit cholinomimetic properties. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 9, pp. 252–255, September, 1994 Presented by A. D. Ado, Member of the Russian Academy of Medical Sciences     

Comparative pharmacological analysis of the M-cholinoreceptors inDaphnia and rats

The efficacy of M-cholinolytics in the prevention of the toxic effect of some cholinomimetics is comparatively assessed in experiments onDaphnia magna and albino rats. It is proposed that the M-cholinoreceptor population is heterogeneous inDaphnia as well as in rats. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 5, pp. 497–499, May, 1994 Presented by S. N. Golikov, Member of the Russian Academy of Medical Sciences     

State of ovarian function in experimental hyperthyroidism and hyperthyrotropinemia

The effect of experimental hyperthyroidism and hyperthyrotropinemia on histophysiological processes in the female reproductive system is studied. Thyroid hormones and thyrotropin are found to exhibit a pronounced modulatory effect on morphogenetic processes in the female gonad. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 10, pp. 422–424, October, 1995     

Effect of chorionic gonadotropin on lactate dehydrogenase and alcohol dehydrogenase activity in the pathologically altered liver

Chorionic gonadotropin is shown to alter lactate dehydrogenase and alcohol dehydrogenase activity in the pathologically altered liver and to exert a regulatory effect on the catalytic properties of these enzymes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 6, pp. 590–591, June, 1994 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

Effects of the membrane stabilizer ajmaline and the local anesthetic trimecaine on the pharmacological effects of strophanthinin vivo andin vitro

Under conditions of simulated circulation failure in rats ajmaline increases tolerance for strophanthin cardiotoxicity to a greater extent than trimecaine. In isolated preparations of frog myocardium both antiarrhythmic agents somewhat weaken the inotropic effect of the cardiac glycoside and virtually do not influence its chronotropic effect. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 1, pp. 59–61, January, 1994. Presented by P. V. Sergeev, Member of the Russian Academy of Medical Sciences     

A study of the mechanism of action of befol on Ca2+ metabolism in cardiomyocytes using a FURA-2 fluorescent probe

The dynamics of the Ca-response of cardiomyocytes is studied and the efficiency of befol, verapamil, and amiodarone is compared using various experimental models of stimulation of [Ca²⁺]_i. Befol (1–5 μM) is shown to inhibit the caffeine-and strophanthin G-induced rise of [Ca²⁺]_i. Unlike verapamil and amiodarone, befol exhibits no Ca-blocking activity in modeled K-depolarization. It is concluded that the cardiotropic effect of befol is mediated through its primary action on Na⁺/Ca²⁺ exchange in cardiomyocytes, while the cardioplegic effect of verapamil and amiodarone is due to their ability to block the slow Ca²⁺ inward current. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 3, pp. 288–291, March, 1996