Pharmacological analysis of regulation of phosphocreatine and ATP metabolism in resting skeletal muscle.

Phosphocreatine and ATP metabolism in the gastrocnemius muscle of rats was studied using 32P. Infusion of acetylcholine decreased utilization of energy in the resting muscle, probably as a result of lowered tonus of the resting muscle in analogy to the changes following muscle relaxation with tubocurarine or denervation. Isoprenaline, adrenaline and noradrenaline accelerated incorporation of 32P in phosphocreatine and ATP and depleted their reserves, and phenylephrine had an opposite effect. Ligation of the adrenals slowed the rate of this metabolism. Presumably regulation of energetic metabolism and energy consumption in resting skeletal muscle is dependent on two mechanisms, one of which is connected witly with liberation of adrenaline and its access to the muscle.