title: Functional role of Na+/H+ exchanger in Ca2+ influx mediated via human endothelin type A receptor stably expressed in Chinese hamster ovary cells.
abstract: This study examines the functional role of Na+/H+ exchanger (NHE) in Ca2+ influx mediated by human endothelin type A receptor (ET(A)R) expressed in Chinese hamster ovary (CHO) cells. Endothelin-1 (ET-1) increased extracellular acidification rate (ECAR), which was abolished by 5-(N-ethyl-N-isopropyl)amiloride (EIPA), an NHE inhibitor. EIPA and KB-R7943, a Na+/Ca2+ exchanger (NCX) inhibitor, inhibited ET-1-induced sustained increases in intracellular Ca2+ concentration ([Ca2+]i), and EIPA had no effect on [Ca2+]i after KB-R7943 treatment. ET-1-elicited sustained [Ca2+]i increase was suppressed by reducing extracellular Na+ concentration. These results suggest that possible coupling of NHE with NCX via Na+ transport is involved in ET(A)R-mediated sustained [Ca2+]i increase.
authors.affiliation: Department of Cellular Pharmacology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Horinouchi
authors.forename: Yumie
authors.initials: Y
authors.lastname: Miyake
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nishiya
authors.forename: Arata
authors.initials: A
authors.lastname: Nishimoto
authors.forename: Shigeru
authors.initials: S
authors.lastname: Morishima
authors.forename: Ikunobu
authors.initials: I
authors.lastname: Muramatsu
authors.forename: Soichi
authors.initials: S
authors.lastname: Miwa
mesh_terms: D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D019332:Endothelin-1 / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D044022:Receptor, Endothelin A / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D019831:Sodium-Calcium Exchanger / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*
chemical_list: D019332:Endothelin-1; D044022:Receptor, Endothelin A; D019831:Sodium-Calcium Exchanger; D017923:Sodium-Hydrogen Exchangers; D012964:Sodium; D002118:Calcium