The rôle of oxidation in maintaining the dynamic equilibrium of the muscle cell

Abstract

It is possible by the methods described in the preceding paper to determine directly, as a deflection on the galvanometer scale, the rate at which heat is being liberated by a muscle at rest on a thermopile. In all that follows this resting heat-rate will be expressed (unless otherwise stated) in grm. -cms. of energy per gramme of muscle per minute, the muscle being weighed, after removing adherent moisture by filter-paper, at the end on an experiment. These units can be converted to grm. -calories per gramme per minute by dividing by 42,400, or to grm. -calories per gramme per hour by dividing by 707. Absolute quantities of heat will be expressed in grm. -cms. per gramme of muscle: these can reduced to grm. -calories per gramme of muscle by dividing by 42,400. In every case the sartorius muscles of a frog were used: Rana temporaria and R. esculenta were employed indiscriminately, no difference being found between them. After careful dissection the muscles were mounted on the thermopile and immersed for 1 to 3 hours in Ringer's solution made with glassdistilled water, and containing sodium phosphate ( p H 7·2, 7 to 15 mgs. per cent. P, see preceding paper). In most cases oxygen was bubbled through the solution, to assist in temperature equalisation, to keep the muscle well oxygenated, and to allow it to recover from stimulation necessarily occurring during dissection.