title: Inhibition of calcium uptake, sodium uptake, and catecholamine secretion by methoxyverapamil (D600) in primary cultures of adrenal medulla cells.
abstract: The calcium-entry antagonist D600 (methoxyverapamil) inhibited nicotine- and veratridine-induced 45Ca2+ uptake, 22Na+ uptake, and catecholamine secretion in primary cultures of bovine adrenal medulla cells. Inhibition of nicotine-induced effects occurred at D600 concentrations approximately 3-10-fold lower than those needed to produce similar inhibition of veratridine-induced effects. Inhibition of the veratridine-induced effects was competitive, but inhibition of the nicotine-induced effects was not competitive. These results suggest that D600, in addition to blocking "slow" Ca2+ channels and tetrodotoxin-sensitive Na+ channels also blocks nicotine transmission, possibly either by noncompetitively inhibiting the interaction of nicotine with the receptor binding site or by blockade of the receptor-associated ion conductance channel.
mesh_terms: D000313:Adrenal Medulla / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002395:Catecholamines / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D005711:Gallopamil / Q000494:pharmacology*; D007700:Kinetics; D009538:Nicotine / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology; D014700:Verapamil / Q000031:analogs & derivatives*; D014701:Veratridine / Q000494:pharmacology
chemical_list: D002395:Catecholamines; D005711:Gallopamil; D013779:Tetrodotoxin; D009538:Nicotine; D014701:Veratridine; D012964:Sodium; D014700:Verapamil; D002118:Calcium