title: Effects of DJ-7141, a new alpha 2-adrenoceptor agonist, on catecholamine secretion from isolated bovine adrenal medullary cells.
abstract: The effects of a newly synthesized alpha 2-adrenoceptor agonist (an imidazole derivative, DJ-7141) on catecholamine secretion from isolated bovine adrenal medullary cells were examined. DJ-7141 did not affect basal catecholamine secretion, but inhibited catecholamine secretion induced by stimulation of the nicotinic ACh receptor. This inhibitory effect of DJ-7141 was less than that of clonidine, another alpha 2-agonist. DJ-7141 also inhibited [45Ca]2+ uptake by the cells induced by nicotinic stimulation. DJ-7141 did not affect catecholamine secretion induced by high K+ concentration. Its inhibitory effect on nicotine-induced catecholamine secretion was not restored by increase in either the nicotine or Ca2+ concentration of the medium, suggesting that it interfered with the coupling between nicotinic ACh receptor stimulation and Ca2+-channel activation. The inhibitory effect of DJ-7141 seemed to be independent of its effect on alpha 2-adrenoceptors, because its effect was not antagonized by the alpha 2-adrenoceptor antagonists yohimbine and DG-5128, which both had no effect on either basal or nicotine-induced catecholamine secretion.
mesh_terms: D000313:Adrenal Medulla / Q000378:metabolism*; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism*; D002417:Cattle; D007093:Imidazoles / Q000494:pharmacology*; D066298:In Vitro Techniques; D009538:Nicotine / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D000316:Adrenergic alpha-Agonists; D002395:Catecholamines; D007093:Imidazoles; D015016:Yohimbine; D009538:Nicotine; C049769:DJ 7141; D002118:Calcium