Release of catecholamines from perfused cat adrenal gland by veratridine.

Abstract

Experiments were done to verify the existence of fast Na channels in the adrenal chromaffin cell membrane and to assess their contribution to the physiological release of catecholamines. Veratridine was used to activate Na channels. Veratridine caused secretion of catecholamines from perfused cat adrenal gland. Secretory response to veratridine was Ca dependent and abolished by tetrodotoxin. Secretion of catecholamines by acetylcholine was only partially blocked by tetrodotoxin. The adrenal chromaffin cell membrane contains fast Na channels directly comparable to those of impulse-propagating neurons, but they do not appear to be essential in the secretory response to acetylcholine or splanchnic nerve stimulation.