The relationship between arachidonic acid release and catecholamine secretion from cultured bovine adrenal chromaffin...

Increased arachidonic acid release occurred during activation of catecholamine secretion from cultured bovine adrenal medullary chromaffin cells. The nicotinic 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 catecholamine secretion. Like catecholamine secretion, the DMPP-induced [3H]arachidonic acid release was calcium-dependent and was blocked by the nicotinic antagonist mecamylamine. Depolarization by elevated K+, which induced catecholamine secretion, also stimulated arachidonic acid release. Because arachidonic acid release from cells probably results from phospholipase A2 activity, our findings indicate that phospholipase A2 may be activated in chromaffin cells during secretion.