Effect of NO-synthase inhibitor L-NAME on occlusion and reperfusion arrhythmias in cats

On the model of occlusion/reperfusion arrhythmia in cats it was shown that repeated injections of the NO-synthase inhibitor L-NAME decreased the incidence of occlusion arrhythmias (to 40%), eliminated reperfusion-induced ventricular fibrillation, and drastically reduced the latency of occlusion arrhythmias. A single injection of L-NAME (20 mg/kg) immediately before ligation of the coronary artery did not decrease the incidence of occlusion and reperfusion arrhythmias. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 5, pp. 509–511, May, 1999     

Is nitric oxide involved in the adaptation to the stress-induced damage?

The iron dinitrosyl complex (a NO donor), adaptation to stress, and their combination suppress the stress-induced ulcer formation. Nω-nitro-L-arginine, a NO synthetase inhibitor, reduce the antistress effect of adaptation. Severe stress induces a sharp decrease in the NO production in the liver and brain. After adaptation to stress, the NO production in the liver and brain does not differ significantly from control levels. However, adaptation attenuates a decrease in the NO production in the liver caused by severe stress. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 9, pp. 274–277, September, 1998     

Thermal adaptation activates HSP70 synthesis, inhibits overproduction of nitric oxide, and protects the body from acute hypotension during heat shock

The role of HSP70 and nitric oxide in antihypotensive effects of thermal adaptation was studied. Western blot analysis and electron paramagnetic resonance were used to determine the contents of HSP70 and nitric oxide. Protective effect of adaptation was evaluated by the limitation of blood pressure drop after heat shock. The formation of protective effects, accumulation of HSP70, and development of the ability to decrease nitric oxide overproduction had similar dynamic patterns and appeared at the same period. Quercetin, an inhibitor of HSP70 synthesis, prevented the development of protective effects. The data suggest that HSP70 accumulated during adaptation prevents heat shock-induced hypotension by restricting NO over-production and interfering with its cytotoxic effects. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 11, pp. 507–510, November, 1999     

Seasonal differences in the development of heightened resistance of the isolated heart during adaptation to physical exercise

Substantial seasonal differences are found in the development of the cardioprotective effect of adaptation to physical exercise: in winter such adaptation results in an increase of the resistance of the isolated heart to the contracture and arrhythmogenic effects of ischemia and reperfusion, while in summer the anticontracture effect is absent and the antiarrythmic effect is significantly lowered. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 9, pp. 299–301, September, 1995 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Increased generation of nitric oxide in tissues of rats following their adaptation to short-term stress (An EPR study)

Adaptation of rats to short-term immobilization stress increases the ability of their isolated organs to generate nitric oxide (NO): its spontaneous release by the liver, gut, heart, and kidney tissues rises 2- to 4-fold and its carbachol-stimulated release by these tissues rises 4- to 5-fold. It is suggested that such adaptation leads to rapid NO generation in the adapted animal in response to exogenous or endogenous stimuli and thus increases the efficacy of defense reactions. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 3, pp. 242–244, March, 1994 Presented by D. S. Sarkisov, Member of the Russian Academy of Medical Sciences     

Relationship of adaptive capabilities in athletes to the type of reaction of their opioid system to stressful physical exercise

Eleven highly skilled skiers are examined during and after prolonged exercising on a bicycle ergometer at a Vo₂ equal to 80% of the maximum. Parameters of mechanical work, Vo₂, plasma lactate concentration, and activity of δ-type opioid receptor ligands are recorded. The opioid system is found to develop two types of reaction to the exercise: activation in the course of work on the ergometer with a tendency toward normalization in the recovery period (Type A) or inhibition during the exercise (Type B). The reaction of Type B involved a rapid increase in the activity of the opioid system immediately after the exercise in some cases and a further fall in the activity of plasma opioids in others. Skiers with Type B reaction performed a lesser amount of work at a higher energy cost than did those with Type A. It is concluded that the latter type of reaction is more efficient than the former. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 8, pp. 135–138, August, 1996     

Increased resistance to heat shock of isolated hearts from rats adapted to moderate physical exercise

Hearts isolated from rats adapted to physical activity through moderate regular exercise (swimming) were more resistant to heat shock than hearts from unadapted controls. Thus, 15-min perfusion of control hearts with a solution heated to 42°C significantly depressed contraction amplitudes and caused a contracture amounting to 36% of the initial contraction amplitude, as well as increased release of creatine kinase into the perfusate. In the hearts from adapted rats, contraction amplitude was, on average, 2.3-fold greater and the contracture 3.2 times less marked than in the control animals; the test and control hearts did not differ significantly in the release of creatine kinase. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 3, pp. 256–258, March, 1995 Presented by S. S. Debov, Member of the Russian Academy of Medical Sciences     

Effect of adaptation to moderate physical loads on the increased resistance of the isolated heart to ischemia and reperfusion

Adaptation to physical loads elicits pronounced anti-ischemic and antireperfusion effects on the isolated heart. By the 20th min of total ischemia contracture in the hearts of adapted animals is much less than that in the control group. During reperfusion of hearts from adapted animals the degree of restoration of the contractile force was 6-fold higher, contracture was lesser, and the total period of tachycardia and fibrillation were 3-fold shorter than in the control. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 25–27, January, 1995 Presented by S. S. Debov, Member of the Russian Academy of Medical Sciences     

Effect of pulsed infrared laser radiation on DNA synthesis in tissues of intact rats and during strenuous physical exercise

The motor zone of the rat brain cortex is subjected to pulsed infrared (0.89 μ) laser radiation, which is found to stimulate DNA synthesis both in intact animals and after strenuous physical exercise (swimming). Preliminary laser irradiation exerts a stress-limiting effect on cells of the brain cortex and thymus but does not prevent swimminginduced reduction of³H-thymidine incorporation in nuclear DNA of muscles. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 6, pp. 625–627, June, 1995 Presented by V. M. Bogolyubov, Member of the Russian Academy of Medical Sciences     

Relationship between strenuous physical exercise and immediate type allergy

Daily intense exercise prevents the development of immediate type allergy in subjects of any age due to inhibition of all three stages of allergy mechanism.     

In Vivo Accumulation of nitric oxide in blood vessels

Against the background of NO-synthase blockade, diethyldithiocarbamate had no effect on the tone of isolated rat aorta, but induced relaxation of aorta preparations isolated afterin vivo NO accumulation and isolated aorta incubated with dinitrosyl iron complex. Guanylate cyclase inhibitor methylene blue prevented the relaxation induced by diethyldithiocarbamate. These data suggest that accumulation of NO in the organism can result in its accumulation in the vessel wall. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 6, pp. 629–632, June, 1999     

Nitric oxide synthase in bronchial epithelium and nitric oxide metabolites in the lungs of rats with bronchial asthma after fenoterol inhalation

Nitric oxide synthase of the bronchial epithelium and concentrations of nitric oxide metabolites (NO₂ ⁻ and NO₃ ⁻) in bronchoalveolar lavage fluids were measured in rats with bronchial asthma after fenoterol inhalation. It was suggested that nitric oxide-ergic mechanisms can mediate the effects of inhaled β₂-adrenergic agonists. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 8, pp. 176–179, August, 2000     

Adaptation to physical exercise increases expression of Ca-ATPase gene in myocardial sarcoplasmic reticulum

Gene expression of the key enzyme of the myocardial sarcoplasmic reticulum Ca²⁺-pump, SERCA-2a isoform was assayed in rats during adaptation to physical exercise (forced swimming). The expression was measured by Northern blot hybridization with subsequent densitometry of the autoradiograms. The signal of mRNA encoding SERCA-2a was referenced to the mRNA signals of marker proteins (S4 and S9 ribosomal proteins, cytoskeletal β-actin and glyceraldehyde-3-phosphate dehydrogenase). The SERCA-2a gene expression gradually increased during adaptation as evidenced by the increased content of SERCA-2a mRNA in particular higher intensity (optical density) of the mRNA signals in autoradiograms. The adaptation-induced increase in the power of the sarcoplasmic reticulum Ca²⁺-pump can be attributed to activated synthesis and accumulation of SERCA-2a isoform. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 7, pp. 24–28, July, 1999     

Role of nitric oxide in modulation of afferent impulses in cutaneous branches of somatic nerves by polarized light

Subcutaneous injection of L-NAME inhibited afferent impulse activity inn. ischiadicus andn. saphenus and abolished the increase in this activity induced by stimulation of mechanoreceptors after skin irradiation with polarized light with various spectral characteristics. Subsequent subcutaneous injection of sodium nitroprusside restored the pattern of afferent impulse activity in these nerves during repeated skin irradiation with polarized light. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 8, pp. 140–143, August, 2000     

Role of nitric oxide in the mechanisms of Verograffin nephrotoxicity

Nephrotoxicity of radiopaque agents and the role of nitric oxide in its realization are studied in Wistar rats with Verograffin-induced acute renal insufficiency. Experiments demonstrate a significant decrease in nitric oxide production in the kidneys due to inhibition of constitutive NO-synthetase and disturbances of renal function, hemodynamics, and electrolyte balance. These changes are prevented by simultaneous injection of verapamil. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 10, pp. 396–399, October, 1997     

Response to airway phagocytes to lung damage before and after strenuous physical exercise

Quantitative ratios between alveolar polymorphonuclear leukocytes (PML) and macrophages and the ingesting and reducing potentials of these phagocytic cells were studied after lung damage in unstressed mice and mice that had just been stressed by strenuous physical exercise (swimming for 60 min). Three days after the lung damage induced in unstressed mice by AgNO₃ (0.1 ml instilled intratracheally), PML numbers in the airway lumens were significantly increased, while the bronchoalveolar lavage fluid samples taken on day 14 after lung damage indicated intensified macrophage activity. In the mice instilled with AgNO₃ immediately after being stressed, the recruitment of PML and macrophages to the lungs was markedly decreased, although the percentage of macrophages reducing nitro blue tetrazolium had significantly increased. That the lungs of stressed mice sustained less injury than those of unstressed animals was indicated by the finding that lactate dehydrogenase activity in the cell-free fraction of bronchoalveolar lavage fluid was less damaged in response to intratracheal instillation of the destructive agent. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 6, pp. 593–596, June, 1995 Presented by V. P. Kaznacheev, Member of the Russian Academy of Medical Sciences     

Opposite effect of adaptation to physical exercise on myocardium and skeletal muscle. Ca-transporting system of the sarcoplasmic reticulum and antioxidant defense enzymes

Adaptation to physical exercise was achieved via 60-min sessions of swimming at 32°C for 45 days, the duration of swimming being increased from 15 to 60 min during the first 14 days. Under these conditions, against the background of reduced catalase and superoxide dismutase activity the Ca-transporting system of the sarcoplasmic reticulum in the heart is shown to work more effectively: Ca²⁺ transport is characterized by a higher initial rate and is inactivated 1.5 times more slowly byin vitro-induced lipid peroxidation and not inhibited by high concentrations of free Ca²⁺. In the skeletal muscle, on the other hand, catalase and superoxide dismutase activity rise, but this does not improve the functioning of the Ca pump: the initial rate of Ca²⁺ transport drops, its resistance to autooxidation is not increased in comparison with the control, and the resistance of the Ca²⁺-transporting system to the inhibiting influence of free Ca²⁺ is lowered. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, No. 6, pp. 623–628, June, 1996     

Hypotensive effect and tissue distribution of the dinitrosyl iron complexes, a nitric oxide donor

Hypotensive effect of the dinitrosyl iron complexes, an NO donor, is compared with distribution of these complexes in organs and tissues after their intravenous administration to wakeful animals. Hypotensive effect of iron complexes depended on dose and postinjection time. There was a strong correlation between hypotensive effect and the content of dinitrosyl iron complex in the studied organs. Effective dose of dinitrosyl iron complexes that did not provoke adverse effects was about 200 mg/kg. This preparation is a prospective source of NO to treat and prevent pathological states related to NO deficiency. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 1, pp. 30–33, January, 1998     

Possible role of nitric oxide in pathologies of the central nervous system

Nitric oxide is a gaseous chemical meassenger involved in the regulation of respiration, cardiovascular homeostasis, immunity, macrophagal activity, gene expression, morphogenesis, synaptic plasticity of the nervous tissue, memory, and release of neurotransmitters. This compound acts as a pathological factor in the states associated with neurodegeneration, ischemia, stroke and convulsions. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 5, pp. 484–490, May, 1997