Increasing effect of caffeine on the oxygen consumption of the skeletal muscle.

In 1937, SASLOW1) reported that the oxygen consumption of the skeletal muscle was increased by subcontracture dose of caffeine. AXELSON2) observed the mechanical change of skeletal muscle induced by caffeine and pointed out the fact that caffeine was a useful agent for the analysis of excitation-contraction coupling mechanism. He found that caffeine was also able to induce the contracture in the K-depolarized muscle. In this case, caffeine had no relation to the electrical properties of the cytoplasmic membrane of the muscle. On the other hand, in the study of potassium effect on the heat production of the muscle. HILL and HOWARTH3) reported that the membrane properties controlled directly the rate of the heat production, having no relation to the contracture of the muscle. Similar fact was ascertained recently by MOMMAERTS4) in the case of the anaerobic glycolysis of the muscle. In the present paper, the authors would like to report the effects of caffeine on the oxygen consumption, the height of contracture, phosphate com-