Differential requirements for Ca2+ concentrations for catecholamine release and biosynthesis in isolated bovine adrenal chromaffin cells.
Differential effects of [Ca2+] on catecholamine release and biosynthesis in isolated bovine adrenal chromaffin cells were investigated. Carbamylcholine, an agonist of the nicotinic and muscarinic acetylcholine receptor, or Na+ deprivation in the incubation medium, stimulated catecholamine release and biosynthesis in these cells. The concentrations of extracellular [Ca2+] which stimulate catecholamine biosynthesis were less than those which stimulate catecholamine release. An increase in intracellular levels of free Ca2+ ([Ca2+]i) induced by Na+ deprivation was dependent on extracellular [Ca2+]. These results indicate that, in bovine adrenal chromaffin cells, catecholamine biosynthesis is regulated by lower levels of [Ca2+]i than is catecholamine release.
Houchi
H
H
Department of Pharmacology, School of Medicine, University of Tokushima, Japan.
Yoshizumi
M
M
Ishimura
Y
Y
Oka
M
M
D000313:Adrenal Medulla / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D002837:Chromaffin Granules / Q000378:metabolism*; D004837:Epinephrine / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D012964:Sodium / Q000172:deficiency
D012964:Sodium; D002118:Calcium; D009638:Norepinephrine; D004837:Epinephrine