title: Uptake of [3H]-nicotine and [3H]-noradrenaline by cultured chromaffin cells.
abstract: Three day-old cultured bovine adrenal chromaffin cells incubated at room temperature with Krebs-HEPES solution containing different concentrations of [3H]-nicotine, took up and retained increasing amounts of the drug by a mechanism that did not saturate. Concentrations of cold nicotine as high as 100 microM did not alter the amount of [3H]-nicotine retained by cells. Imipramine, cocaine, tetracaine or mecamylamine, at concentrations (10 microM) that blocked the catecholamine secretory effects of nicotine completely, did not modify the uptake of [3H]-nicotine. Both imipramine and cocaine drastically inhibited [3H]-noradrenaline uptake by cells in a concentration-dependent manner (IC50S of 0.08 and 1 microM, respectively). These data indicate that the secretory effects of nicotine are not coupled to its previous uptake into cells, and are evidence in favour of a site of action for nicotine located in or at the surface of the chromaffin cell membrane.
mesh_terms: D000313:Adrenal Medulla / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects; D002478:Cells, Cultured; D002838:Chromaffin System / Q000378:metabolism*; D003042:Cocaine / Q000494:pharmacology; D007099:Imipramine / Q000494:pharmacology; D008464:Mecamylamine / Q000494:pharmacology; D009538:Nicotine / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D013748:Tetracaine / Q000494:pharmacology
chemical_list: D013748:Tetracaine; D008464:Mecamylamine; D009538:Nicotine; D003042:Cocaine; D007099:Imipramine; D009638:Norepinephrine