EFFECTS OF CHLORPROMAZINE, PHENOXYBENZAMINE, DIBENAMINE AND CALCIUM ON ELECTRICAL AND MECHANICAL RESPONSES TO POTASSIUM IN GUINEA-PIG TAENIA COLI

¹ Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi

Using the sucrosegap technique, the effects of chlorpromazine (10^-5 M), phenoxybenzamine (10^-4 M) and Dibenamine (10^-4 M) on the mechanical and electrical responses to potassium have been investigated. The mechanical response to potassium was inhibited before the electrical response was affected by these agents. The inhibition of mechanical response did not occur in high calcium medium. Mechanical and electrical responses to acetylcholine were inhibited by chlorpromazine, phenoxybenzamine and Dibenamine in normal or high calcium media. These results suggest that potassium contracture involves calcium and that chlorpromazine, phenoxybenzamine and Dibenamine compete with calcium.