[Effect of nitric oxide on the efficiency of oxygen consumption by the working skeletal muscle in fatigue].
The influence of NO on the efficiency of oxygen usage by a skeletal muscle under fatigue of dog's gastrocnemius muscle was investigated. In control experiments was shown, that 10 short-term (30") electrical stimulation (8 Hz, 5 ms, 20 V) with 5" interval resulted in significant reduction of the muscle contraction force (more than 40%) and increased considerably oxygen cost of muscle gastrocnemius work (more than 130%) compared to the initial parameters. The registered depression of the muscle contraction force testified to development of gastrocnemius muscle fatigue, accompanied by mitochondrial factor (MF) appearance in blood from femoralis vein, which, as shown by us earlier, is a marker of the mPTP opening. Injection of L-NMMA, a NOS inhibitor (2.7 mg/kg, i.a.) resulted in pronounced fall (more than 1.5 times) of the initial force parameters, in comparison with the control experiments. Under these conditions the magnitude of oxygen cost of gastrocnemius muscle work exceeded control parameters considerably. The development of gastrocnemius muscle fatigue under L-NMMA action was accompanied, as well as in the control condition by the mPTP opening. The preliminary injection of sodium nitroprusside, a NO donor (0.2 mg/kg, i.v.) prevented a fall of muscle contractions force and considerable inhibition of oxygen usage efficiency by gastrocnemius muscle under conditions similar to control. Furthemore, gastrocnemius muscle fatigue was not developed, and MF concentration in blood from femoralis vein was much lower, than in the control experiments, that testified to absence of the mPTP opening. Apparently, preliminary short-term (30") electrical stimulation (8 Hz, 5 ms, 20 V) with 2' interval, created the precondition effect and raised the level of authentic NO. Under these conditions, as well as under preliminary injection of the NO donor, we did not register the marked inhibition of oxygen usage efficiency and development of gastrocnemius muscle fatigue. At the same time, MF in blood from v. femoralis was practically absent, that testify to absence of the mPTP opening. Thus, NO in physiological concentration by inhibition of mPTP opening, can prevent decrease of oxygen usage efficiency and development of the working skeletal muscle fatigue.
Bohuslavs'kyĭ
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AIu
Dmytriieva
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Sahach
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D000818:Animals; D004285:Dogs; D004558:Electric Stimulation; D007473:Ion Channels / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D010101:Oxygen Consumption / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D019323:omega-N-Methylarginine / Q000494:pharmacology
D007473:Ion Channels; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D020030:Nitric Oxide Donors; D019323:omega-N-Methylarginine; D009569:Nitric Oxide