Drug and ion effects in frog muscle

Procaine, cocaine, pyribenzamine, antistine, and phosphate decrease the uptake of water by frog sartorii in a Ringer solution in which potassium has been substituted for sodium; all but the last two leave the swelling in hypotonic Ringer practically unaltered. They also decrease the depolarizing action of potassium. These effects are considered indicative of reduced membrane permeability to potassium.