title: Ionophore-induced Cl- transport in human erythrocyte suspensions: a multinuclear magnetic resonance study.
abstract: To investigate the effect of ionophores on Cl- distribution in human erythrocyte suspensions, we measured the membrane potential by using 19F and 31P NMR methods. Incubation of human erythrocytes with 0.005 mM of the neutral ionophores valinomycin and nonactin resulted in membrane potentials of -21.2 and -17.8 mV in the presence and absence of DIDS. However, 0.020 mM of the carboxylic ionophores lasalocid, monensin, and nigericin yielded membrane potentials similar to those measured in the absence of ionophore (-9.4 mV). In methanol, the 35Cl- NMR linewidth in the presence of valinomycin was twice as broad as those observed in the presence of carboxylic ionophores, suggesting that neutral ionophores induce Cl- efflux in part via ion pairing.
authors.affiliation: Department of Chemistry, Loyola University of Chicago, Illinois 60626.
authors.forename: L
authors.initials: L
authors.lastname: Wittenkeller
authors.forename: D
authors.initials: D
authors.lastname: Mota de Freitas
authors.forename: R
authors.initials: R
authors.lastname: Ramasamy
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002712:Chlorides / Q000097:blood*; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000502:physiology*; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007476:Ionophores / Q000494:pharmacology*; D007700:Kinetics; D007832:Lasalocid / Q000494:pharmacology; D018942:Macrolides; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008564:Membrane Potentials / Q000187:drug effects; D008985:Monensin / Q000494:pharmacology; D009550:Nigericin / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D002712:Chlorides; D007476:Ionophores; D018942:Macrolides; D014634:Valinomycin; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D008985:Monensin; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D009550:Nigericin; C050476:nonactin; D007832:Lasalocid