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

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Abstract
The resting heat-rate of sartorius muscles has been investigated, in O and under strictly anaerobic conditions. The resting heat-rate in O agrees with existing determinations of the rate of O consumption. Survival in O, and stimulation followed by recovery in O, tend to diminish rather than to increase the resting heat-rate. The minimum resting heat-rate in the absence of O is attained within 1/2 hr. in N, and is sufficiently accounted for by lactic acid production. Stimulation produces an immediate increase in the anaerobic resting heat-rate, which under conditions of advanced fatigue may reach considerable values. This increase persists for many hrs., long after the muscle has become inexcitable. A linear relation exists between the increment in anaerobic resting heat-rate and the energy liberated by previous anaerobic stimulation. "Electrocution," i.e., excessive electrical stimulation, produces a great increase in the anaerobic resting heat-rate. The absolute values are discussed. The quantities involved are so large that the phenomenon described can not be due simply, or mainly, to enhanced lactic acid formation: it must be attributed to other anaerobic breakdowns involving far more energy than this. Resting anaerobic survival without stimulation leads gradually to the same high heat-rate. The increased resting heat-rate provoked by anaerobic stimulation, or survival, has a temp. coefficient of 2.7 for 10[degree]C. Increased acidity is not the cause of the phenomenon. Immersing a muscle in pure CO2 tends rather to decrease than to increase the resting heat-rate. The effect of anaerobic stimulation in increasing the resting heat-rate can be reversed, partially or completely, by recovery in O. The possibility of oxidation leads to the inhibition of reactions previously occurring. The role of oxidation in maintaining the chemical and physical architecture of the cell is discussed. The degenerative changes set up by anaerobic stimulation, or survival, proceed at a rate determined at any moment by the degree of 0-want. Oxidation at rest is concerned with upholding the integrity of boundaries or membranes, which are essential if the organized system is not to become a chaos of biochemical processes.

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