Studies on isolated smooth muscle cells. II. Potentiation of calcium contraction of isolated smooth muscle cells from vas deferens of guinea pig by cocaine.

Single smooth muscle cells were isolated from vas deferens of guinea pig and effect of cocaine on calcium contraction of the individual cells under partially depolarized condition was examined. Among the isolated cells, a few cells were contracted by 20 mM calcium chloride in medium containing 60 mM potassium chloride. Cocaine increased the ratio of contracted cells. The result suggested that cocaine facilitated calcium contraction of individual cells in the tissue and induced larger contraction of the tissue.