Abstract
Increased arachidonic acid-release occurred during activation of catecholamine [CA] secretion from cultured bovine adrenal medullary chromaffin cells. The nicitonic agonist 1,1-dimethyl-4-phenylpiperazinium (DMPP) caused an increased release of preincubated [3H]arachidonic acid over a time course which corresponded to the stimulation of Ca secretion. Like Ca secretion, the DMPP-induced [3H]arachidonic acid release was Ca-dependent and was blocked by the nicotinic antagonist mecamylamine. Depolarization by elevated K+, which induced Ca secretion, also stimulated arachidonic acid release. Because arachidonic acid release from cells probably results from phospholipase A2 activity, phospholipase A2 may be activated in chromaffin cells during secretion.