A novel DIDS-sensitive, anion-dependent Mg(2+) efflux pathway in rat ventricular myocytes.
The aim of this study was to identify the existence of anion-dependent Mg transport systems in cardiac muscle. DIDS-sensitive and anion-dependent (either Cl(-)(o) or NO(-)(3o)) increases in [Mg(2+)](i) occurred during Mg(2+) loading conditions. Much larger elevations of [Mg(2+)](i) occurred under Cl(-)(o)-free conditions with 0.1 mmol l(-1) DIDS, compared to Cl(-)(o) replacement alone. All these effects were abolished in Mg(2+)(o)-free medium. These data suggest a novel Mg(2+)-anion symport for Mg(2+) efflux against the electrochemical gradient that is fueled mostly by the efflux of an endogenous anion (HCO(-)(3)?), but with a small contribution from intracellular Cl(-) probably supplied via the Cl(-)-HCO(-)(3) exchanger.
Odblom
M P
MP
Department of Biological Sciences, University of Plymouth, Drake Circus, Plymouth, Devon, PL4 8AA, United Kingdom.
Handy
R D
RD
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects*; D002712:Chlorides / Q000494:pharmacology; D016257:Fura-2; D006352:Heart Ventricles / Q000187:drug effects; D017136:Ion Transport / Q000187:drug effects; D008274:Magnesium / Q000032:analysis / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D009566:Nitrates / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013050:Spectrometry, Fluorescence
D002712:Chlorides; D009566:Nitrates; D008274:Magnesium; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D016257:Fura-2