Does acetylcholinesterase inhibition affect catecholamine secretion by adrenomedullary cells?
GROUND: Splanchnic nerve stimulation evokes adrenomedullary catecholamine secretion via acetylcholine release and occupation of nicotinic cholinergic receptors on chromaffin cells. OBJECTIVES: To assess whether among cultured adrenomedullary cells there exists a population that tonically secretes acetylcholine. If so, then blockade of enzymatic breakdown of acetylcholine by addition of a cholinesterase inhibitor to the medium would increase occupation of nicotinic receptors by endogenous acetylcholine and thereby induce catecholamine release. METHODS: Primary cultures of bovine adrenomedullary cells in 24-well plates (1 million cells per well) were incubated after 48-72 hours with fresh incubation medium (control), medium with added secretagogues (nicotine, angiotensin II, or K+) or the acetylcholinesterase inhibitor, edrophonium (10(-7) to 10(-3) M), for 1-20 minutes. Fractional release rates of epinephrine, norepinephrine and dopamine were compared to a control. We also examined whet
