THE DIFFERENT EFFECTS OF D‐600 (METHOXYVERAPAMIL) ON THE RELEASE OF ADRENAL CATECHOLAMINES INDUCED BY ACETYLCHOLINE, HIGH POTASSIUM OR SODIUM DEPRIVATION

Abstract

1 Bovine adrenal glands were perfused with Locke solution and catecholamine release was induced by acetylcholine, by a depolarizing concentration of potassium, or by omission of sodium from the perfusion fluid. 2 D-600 (methoxyverapamil) at the concentration of 30 μm produced a 23% inhibition of catecholamine release evoked by acetylcholine (0.1 mm) in the presence of physostigmine (10 μm). 3 A concentration of D-600 of 0.3 mm produced 86% and 85% inhibition in the output of catecholamines in response to acetylcholine and high potassium respectively. 4 D-600 (0.3 mm) failed to block the release of catecholamines evoked by sodium deprivation. 5 The results suggest the involvement of intracellular calcium in the exocytotic release of catecholamines induced by sodium omission.