Stimulation of choline/Mg2+ antiport in rat erythrocytes by mefloquine

In non Mg2+-loaded and non malaria-infected rat erythrocytes, mefloquine (100 mu mol(.)l(-1)) stimulated choline/Mg2+ antiport without affecting the Na+/Mg2+ antiport. The stimulation of the choline/Mg2+ antiport by mefloquine, found in this study, and by trifluoperazine and fluvoxamine, reported previously [Ebel et al. Biochem Biophys Acta 2004; 1167: 132-40], was associated with CF3 groups attached to the quinoline or benzene ring. The effect of mefloquine oil choline/Mg2+ antiport in vitro was not related to the antimalarial action of mefloquine in vivo. In rat erythrocytes, the choline/Mg2+ antiport can be differentiated from the Na+/Mg2+ antiport through the use of cinchonine that inhibited the choline/Mg2+ antiport, [Ebel et al. Biochim Biophys Acta 2002; 1559: 135-44], and mefloquine that, stimulated the choline/Mg2+ antiport, whereby the Na+/Mg2+ antiport was not affected by either drug at proper concentrations. The Na+/Mg2+ antiport and choline/Mg2+ antiports behave as different molecular entities.