[Ouabain-sensitive respiration and Na K ATPase of the skeletal muscles and brown fat in cold-adapted rats].

Respiration of the neck muscles and brown adipose tissue of the rats increased as the rats adapted to cold in periodic regimen. The ouabain--sensitive component of the neck muscles respiration did not increase while increasing in the brown adipose tissue. Activity of Na, K-ATPase of the neck and thigh muscles was reduced while increasing in the brown adipose tissue. Sensitivity of Na, K-ATPase of the skeletal muscles to the acetylcholine inhibitory effect considerably increased in the period of cold adaptation. The findings do not confirm assumption of Na--pump involvement in the activation of nonshivering thermogenesis in the skeletal muscles in cold adaptation.