THE EFFECT OF SURFACE-ACTIVE AGENTS ON THE RESTING POTENTIAL OF MUSCLE

The effect of different kinds of detergents on the resting potential of muscle was observed in extirpated twin gastrocnemii of bullfrog for further elucidation of the relation electrogenesis in a living organism bears to the adsorption or to the structure of the biological membrane. The following is a brief description of the results reached. (1) An ionic surface-active agent at a low concentration brought about a marked reduction in the potential of the uninjured part of muscle and had hardly any such effect on the injured part. A non-ionic agent had hardly any action on either of the parts. (2) It was found that the correlation between the concentration of a detergent and the change it produces in the resting potential of muscle is explicable by the equation below: C/E=A'+B'C where A' and B' are constants. It was presumable that there was a parallelrunning relation between the potential change produced by the detergent and the amount of the detergent adsorbed according to Langmuir's adsorption isotherm. (3) The velocity with which the detergent acted was determinable by Wo. Ostwald's equation formulated for measurement of toxic actions. (4) Hardly any correlation was recognizable between the surface activity of a detergent and the change it produced in the resting potential of muscle. (5) A detergent applied produced muscle contracture and made the surface of the muscle white and turbid. These results showed that the potential a detergent (6 different kinds used) can affect is on cell membrane; that a detergent is essentially different from any inorganic ions in the mechanism of action; that it is likely to affect the resting potential because its monomolecular adsorption to the surface of membrane may alter the molecular structure of the membrane by its own penetration or by the consequent disorientation of the component molecules of the membrane.