title: Simvastatin inhibits catecholamine secretion and synthesis induced by acetylcholine via blocking Na+ and Ca2+ influx in bovine adrenal medullary cells.
abstract: Simvastatin, an inhibitor of HMG-CoA reductase, is a potent inhibitor of cholesterol biosynthesis and has beneficial effects in the primary and secondary prevention of cardiovascular diseases. In this study, we report the effects of simvastatin on catecholamine secretion and synthesis in cultured bovine adrenal medullary cells used as a model of sympathetic neurons. Simvastatin inhibited catecholamine secretion induced by acetylcholine, an agonist of the nicotinic acetylcholine receptor; by veratridine, an activator of voltage-dependent Na(+) channels; and by high K(+), an activator of voltage-dependent Ca(2+) channels (IC(50) = 3.8, 7.8, and 6.1 microM, respectively). Simvastatin also suppressed acetylcholine-induced (22)Na(+) influx (IC(50) = 4.3 microM) and (45)Ca(2+) influx (IC(50) = 6.1 microM), veratridine-induced (22)Na(+) influx (IC(50) = 6.6 microM) and (45)Ca(2+) influx (IC(50) = 12 microM), and high K(+)-induced (45)Ca(2+) influx (IC(50) = 11 microM). The reduction of catecholamine secretion caused by simvastatin was not overcome by increasing the concentration of acetylcholine or by treatment with mevalonate, the first metabolite of HMG-CoA. The inhibitory effect of simvastatin on histamine-induced secretion of catecholamines was observed in the presence of extracellular Ca(2+), but not in a Ca(2+)-free medium, suggesting that simvastatin does not interfere with histamine receptors nonselectively. Simvastatin also suppressed acetylcholine-induced [(14)C]catecholamine synthesis from [(14)C]tyrosine as well as tyrosine hydroxylase activity. These findings suggest that simvastatin inhibits catecholamine secretion and synthesis induced by acetylcholine through suppression of Na(+) and Ca(2+) influx in the adrenal medulla and probably in the sympathetic neurons.
authors.affiliation: Department of Pharmacology, University of Occupational and Environmental Health, School of Medicine, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
authors.forename: Taeko
authors.initials: T
authors.lastname: Matsuda
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Toyohira
authors.forename: Susumu
authors.initials: S
authors.lastname: Ueno
authors.forename: Masato
authors.initials: M
authors.lastname: Tsutsui
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Yanagihara
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000313:Adrenal Medulla / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology; D002395:Catecholamines / Q000096:biosynthesis / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006632:Histamine / Q000494:pharmacology; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D008798:Mevalonic Acid / Q000494:pharmacology; D011978:Receptors, Nicotinic / Q000502:physiology; D019821:Simvastatin / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels / Q000502:physiology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D015220:Calcium Channels; D002395:Catecholamines; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D011978:Receptors, Nicotinic; D015222:Sodium Channels; D006632:Histamine; D012964:Sodium; D019821:Simvastatin; D014446:Tyrosine 3-Monooxygenase; D000109:Acetylcholine; D008798:Mevalonic Acid; D002118:Calcium