Open AccessMultiple actions of extracellular ATP on calcium currents in cultured bovine chromaffin cells.
Author(s) -
Marı́a A. Diversé-Pierluissi,
Kathleen Dunlap,
Edward W. Westhead
Publication year - 1991
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.88.4.1261
Subject(s) - depolarization , chromaffin cell , secretion , extracellular , calcium , biophysics , gtp' , electrophysiology , biology , membrane potential , chemistry , microbiology and biotechnology , voltage dependent calcium channel , endocrinology , biochemistry , catecholamine , neuroscience , enzyme , adrenal medulla , organic chemistry
Hormone secretion from chromaffin cells is evoked by calcium influx through voltage-dependent channels in the plasma membrane. Previous studies have shown that ATP, cosecreted with catecholamines from chromaffin granules, can modulate the secretion resulting from depolarization by nicotinic agonists. The immediate effect of ATP is to enhance secretion; more prolonged exposure to the nucleotide results in inhibition. These receptor-mediated actions of ATP involve the activation of at least two separate classes of GTP-binding protein. Results from electrophysiological experiments reported here demonstrate that the modulatory actions of ATP can, in large part, be explained by the effects of the nucleotide on inward calcium current. ATP shows a rapid enhancement and a slower, persistent inhibition of the depolarization-induced inward current.