title: Amphetamine enhances Ca2+ entry and catecholamine release via nicotinic receptor activation in bovine adrenal chromaffin cells.
abstract: Amphetamine, a psychostimulant, has been shown to act as a channel blocker of muscle nicotinic receptors and to induce a Ca(2+)-dependent secretion from adrenal chromaffin cells. In this study, the relationship between amphetamine and nicotinic receptors was studied using bovine adrenal chromaffin cells as a model system. Our results show that D-amphetamine sulfate alone induced an increase in the cytosolic Ca(2+) concentration ([Ca(2+)](c)) and [3H]norepinephrine release in a dose-dependent and extracellular Ca(2+)-dependent manner. Two common nicotinic receptor antagonists, hexamethonium and mecamylamine, suppressed the D-amphetamine sulfate-induced [Ca(2+)](c) rise and [3H]norepinephrine release. In addition, D-amphetamine sulfate inhibited the 1,1-dimethyl-4-phenyl-piperazinium iodide (DMPP)-induced [Ca(2+)](c) rise and [3H]norepinephrine release, but not the high K(+)- or veratridine-induced [Ca(2+)](c) increase and [3H]norepinephrine release. Antagonists, including alpha-bungarotoxin and choline, that are more specific for alpha7 nicotinic receptors were capable of inhibiting the D-amphetamine sulfate-induced [Ca(2+)](c) rise, while D-amphetamine sulfate was found to be capable of inhibiting the [Ca(2+)](c) rise induced by the alpha7-nicotinic receptor agonists, epibatidine and choline. Moreover, D-amphetamine sulfate dose-dependently suppressed [3H]nicotine binding to chromaffin cells. We, therefore, conclude that D-amphetamine sulfate acts as a nicotinic receptor agonist to induce [Ca(2+)](c) increase and [3H]norepinephrine release in bovine adrenal chromaffin cells.
authors.affiliation: Department of Microbiology, Soochow University, Shihlin, Taipei, Taiwan, ROC. psliu@mail.scu.edu.tw
authors.forename: Pei-Shan
authors.initials: PS
authors.lastname: Liu
authors.forename: Chwen-Tzy
authors.initials: CT
authors.lastname: Liaw
authors.forename: Meng-Kai
authors.initials: MK
authors.lastname: Lin
authors.forename: Song-Huah
authors.initials: SH
authors.lastname: Shin
authors.forename: Lung-Sen
authors.initials: LS
authors.lastname: Kao
authors.forename: Lih-Fang
authors.initials: LF
authors.lastname: Lin
mesh_terms: D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002395:Catecholamines / Q000378:metabolism*; D002413:Cations, Divalent / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D011978:Receptors, Nicotinic / Q000378:metabolism* / Q000502:physiology
chemical_list: D002395:Catecholamines; D002413:Cations, Divalent; D011978:Receptors, Nicotinic; D000661:Amphetamine; D002118:Calcium