INTERMITTENT HIPOXIC TRAINING WITH EXOGENOUS NITRIC OXIDE IMPROVES RAT'S
MIOCARD MITOCHONDRIAL OXIDATION AND PHOSPHORILATION UNDER ACUTE HYPOXIA
N. Kurhalyuk
Ivan Franko National University of L'viv,
Hrushevskoho st. 4, L'viv 79005, Ukraine,
e-mail: biolog@franko.lviv.ua
It have been shown that NO plays primary role in several mitochondrial functions in experiments on Wistar rats. Our objective for this study was to investigate whether exogenous NO (L-arginine) modulates the adaptive reactions of rat liver tissue respiration on intermittent hypoxic training (IHT). In control animals the test with acute hypoxia (7% O2, 30 min) provoked sharp augmentation of ADP-stimulating tissue respiration with the increase of respiratory coefficient and phosphorylation rate, the decrease of O2 uptake efficacy and switching the energy supply to succinate oxidation pathway. The same hypoxic test but after 14 days of IHT (10 % O2, 15-min sessions with 15 min rest intervals, 5 times daily) produced a stimulation of oxidative phosphorylation with primary activation of NAD-dependent pathway, the marked increase of ADP/O ratio. The combination of IHT with L-arginine treatment (600 ìg/êg intraperitoneally, daily before IHT sessions) provoked a decrease of tissue oxygen consumption in comparison with untrained animals. L-arginine effects abolished by the NO-synthase blocker L-NNA. We conclude that the combination of IHT which promotes the increase of inner adaptive mechanisms with NO-donors treatment could significantly increase the tolerance to episodes of acute hypoxia.
Key words: intermittent hypoxic training, L-arginine, NO-synthase blocker L-NNA, acute hypoxia.
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