Angiotensin II mediates catecholamine and neuropeptide Y secretion in human adrenal chromaffin cells through the AT1 receptor

Abstract

The aim of the present work was to study the effect of angiotensin II (Ang II) on catecholamines and neuropeptide Y (NPY) release in primary cultures of human adrenal chromaffin cells. Ang II stimulates norepinephrine (NE), epinephrine (EP) and NPY release from perifused chromaffin cells by 3-, 2- and 12-fold, respectively. The NPY release is more sustained than that of catecholamines. We found that the receptor-AT2 agonist, T2-(Ang II 4-8)2 has no effect on NE, EP and NPY release from chromaffin cells. We further showed that Ang II increases intracellular Ca2+ concentration ([Ca2+]i). The selective AT1-receptor antagonist Candesartan blocked [Ca2+]i increase by Ang II, while T2-(Ang II 4-8)2 was ineffective. These findings demonstrate that AT1 stimulation induces catecholamine secretion from human adrenal chromaffin cells probably by raising cytosolic calcium.