The effect of antiarrhythmic drugs on catecholamine secretion from adrenal medullary cells.

Abstract The effects of quinidine, ajmaline and procainamide on the catecholamine(CA) secretion from adrenal medullary cells were examined. The cells were obtained from the bovine adrenal medulla by treatment with collagenase. Quinidine inhibited the CA secretion by 0.1mM carbamylcholine(Cch), excess-potassium(56mM) and 0.1mM veratridine; concentrations of 4×10−7, 2×10−6, 10−6 and 5×10−5M quinidine inhibited the response to Cch by 39.0, 42.2, 82.1 and 9 3.8 %, respectively. Above concentrations of quinidine inhibited the response to excess-potassium by 9.9, 13.7, 31.5 and 46.9 %, respectively. Above concentrations of quinidine inhibited the response to veratridine by 6.7, 26.2, 43.5 and 68.9 %, respectively. Ajmaline and procainamide inhibited the CA secretion only by Cch; concentrations of 2×10−6, 10−5, 5×10−5 and 2.5×10−4M ajmaline inhibited the response to Cch by 19.0, 44.2, 86.4 and 9 4.5 %, respectively. Procainamide at the same concentrations as ajmaline inhibited the response to Cch by 20.1, 34.6, 79.2 and 96.3 %, respectively.