| Abstract: | The working properties and heat formation of skeletal muscles were investigated during contraction in laboratory rats adapted to hypoxia and corresponding controls. During indirect electrical stimulation of the muscle the strength of contraction, work, and fatigue ability of the muscle were determined and the increase in temperature of the muscle as a result of the contraction was measured. Adaptation to hypoxia was shown not to affect the strength of contraction of the muscle or the quantity of work done. However, hypoxia leads to a reduction in the temperature effect of muscular contraction, expressed per unit work done. This indicates an increase in the efficiency of muscular work during adaptation to hypoxia. The fatiguability of muscles is increased in  hypoxic rats. The changes in the energetics of muscular contraction during adaptation to hypoxia and to cold are different in direction.Laboratory of Thermoregulation, Institute of Clinical and Experimental Medicine, Siberian Branch. Academy of Medical Sciences of the USSR, Novosibirsk. Laboratory of Thermoregulation, Institute of Physiology and Experimental Pathology of Highland Areas, Academy of Sciences of the Kirghiz SSR, Frunze. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 3, pp. 259–260, March, 1978. |
