POTASSIUM FLUXES IN FROG SARTORIUS MUSCLE TREATED WITH TETRAALKYLAMMONIUM IONS

¹ Department of Pharmacology, Schools of Medicine and Dental Medicine, University of Connecticut, McCook Hospital, Hartford, Connecticut

Tetrapropyl- (TPA) and tetrabutylammonium (TBA) ions caused a depolarization of frog sartorius muscle fibers bathed in hypertonic solution that was delayed in onset and difficult to reverse. The compounds blocked conduction of the muscle action potentials. When TBA was applied to the muscle for short periods of time, a marked prolongation of the action potential occurred. Muscles exposed to TPA or TBA for two to three hours gained sodium and lost potassium. The decrease of muscle potassium was associated with a decreased rate of uptake of K⁴² and an increase in the rate constant of loss of K⁴². The changes in potassium fluxes produced by TBA occurred also in muscles bathed in sodium chloride-deficient solutions. None of the effects of TPA or TBA was prevented by d-tubocurarine. It was not possible to determine whether the depolarization of the muscle fibers was due to direct interactions of TPA and TBA with cellular processes involved in potassium movement in the muscle fiber or whether the effects of TPA and TBA on potassium fluxes were secomudary to depolarization of the muscle fibers.