THE OXYGEN CONSUMPTION OF FROG MUSCLE IN CHEMICAL CONTRACTURES

¹ From the Department of Physiology, School of Medicine and Dentistry, The University of Rochester, Rochester, New York

1. Contractures produced in the frog sartorius muscles by chemical agents are accompanied by an increased oxygen consumption. This was found true for acids, alkalis, hypertonic NaCl, H₂O, isotonic solution of the sulphate, chloride and sulphocyanide of potassium and of the oxalate and sulphate of sodium, as well as the drugs caffeine, quinine, acetylcholine and nicotine.

2. The ratio of the excess oxygen used to the tension-time developed in the contractures was compared to the same ratio, O₂/Tlt, calculated from heat production measurements in short tetani as found in the literature, and found to be usually somewhat larger but of the same general order of magnitude. This indicates that the same mechanism is responsible for chemical contractures as for tetani but that the energy is used in a more economical manner in the latter.

3. In tetanic contraction the value of this ratio varies from 0.005 to 0.009, while in chemical contracture the typical figure is 0.03. Other figures are obtained as low as 0.004 and as high as 0.19.