Release of (3H)norepinephrine from a clonal line of pheochromocytoma cells (PC12) by nicotinic cholinergic stimulation.
Release experiments were carried out in vitro with a clonal line of rat pheochromocytoma cells (designated PC12) which synthesize and store catecholamines and which, after treatment with nerve growth factor (NGF), cease cell division and extend neuronal-like processes. In the present study, PC12 cells were exposed to [3H]norepinephrine (NE) which they took up and stored in reserpine-sensitive sites. Exposure of such cells to nicotinic cholinergic agonists resulted in release of [3H]NE into the external medium. Release terminated within 1 min and partially returned after 20 min in the absence of agonist. After 1 min of stimulation with nicotine, NGF-treated cells released 5-6% of their contents of [3H]NE while NGF-untreated cells released 1-2%. Release from both NGF-treated and -untreated PC12 cells was inhibited in the absence of Ca2+ or by elevated Mg2+ and was blocked by the nicotinic antagonists D-tubocurarine and mecamylamine (50% inhibition at 0.1 and 0.06 micrometer, respectively). Release was not affected by the presence of tetrodotoxin. Such findings suggest that release of [3H]NE from PC12 cells may be mediated via stimulation of nicotinic acetylcholine receptors and a consequent stimulation-secretion coupling mechanism.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002999:Clone Cells; D004246:Dimethylphenylpiperazinium Iodide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D008274:Magnesium / Q000494:pharmacology; D008464:Mecamylamine / Q000494:pharmacology; D009374:Neoplasms, Experimental / Q000378:metabolism; D009414:Nerve Growth Factors / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism*; D010673:Pheochromocytoma / Q000378:metabolism*; D051381:Rats; D011950:Receptors, Cholinergic / Q000378:metabolism*; D011978:Receptors, Nicotinic / Q000378:metabolism*; D012110:Reserpine / Q000494:pharmacology; D014403:Tubocurarine / Q000494:pharmacology
D009414:Nerve Growth Factors; D011950:Receptors, Cholinergic; D011978:Receptors, Nicotinic; D004246:Dimethylphenylpiperazinium Iodide; D008464:Mecamylamine; D009538:Nicotine; D001285:Atropine; D012110:Reserpine; D008274:Magnesium; D002118:Calcium; D014403:Tubocurarine; D009638:Norepinephrine