title: Sodium/proton exchange in cultured bovine adrenal medullary cells.
abstract: We investigated the presence of Na+/H+ exchange in cultured bovine adrenal medullary cells. The intracellular pH in control cells measured by 5,5-dimethyl[2-14C]oxazolidine-2,4-dione was 7.13 +/- 0.02 (n = 6). Removal of Na+ from the incubation medium shifted the intracellular pH down to 6.67 +/- 0.12 (n = 6). Reintroduction of Na+ to the medium caused a rapid recovery in intracellular pH to 7.20-7.30 that was associated with an increase in uptake of 22Na+ by the cells. Both increases in intracellular pH and uptake of 22Na+ were inhibited by amiloride, an inhibitor of Na+/H+ exchange. The recovery of intracellular pH by addition of Na+ was partially inhibited by quinidine, another inhibitor of Na+/H+ exchange, but not by 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid, an anion-exchange (Cl-/HCO3-) inhibitor. Li+ could substitute for Na+ in the recovery of intracellular pH. Carbachol caused an increase in intracellular pH from 7.12 +/- 0.01 to 7.21 +/- 0.02 (n = 10). This increase in intracellular pH caused by carbachol was inhibited by amiloride. These results suggest the existence of an amiloride-sensitive Na+/H+ exchange that regulates the intracellular pH in adrenal medullary cells.
authors.affiliation: Department of Pharmacology, University of Occupational and Environmental Health, School of Medicine, Kitakyushu, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Yanagihara
authors.forename: K
authors.initials: K
authors.lastname: Yokota
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.forename: A
authors.initials: A
authors.lastname: Wada
authors.forename: Y
authors.initials: Y
authors.lastname: Uezono
authors.forename: F
authors.initials: F
authors.lastname: Izumi
mesh_terms: D000313:Adrenal Medulla / Q000166:cytology / Q000378:metabolism*; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D003470:Culture Media; D004305:Dose-Response Relationship, Drug; D005110:Extracellular Space / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000378:metabolism; D009994:Osmolar Concentration; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology; D017923:Sodium-Hydrogen Exchangers; D013395:Sucrose / Q000494:pharmacology
chemical_list: D002352:Carrier Proteins; D003470:Culture Media; D017923:Sodium-Hydrogen Exchangers; D013395:Sucrose; D000584:Amiloride; D002217:Carbachol; D012964:Sodium