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

In non Mg 2+-loaded and non malaria-infected rat erythrocytes, mefloquine (100 μmol·l -1) stimulated choline/Mg 2+ antiport without affecting the Na +/Mg 2+ antiport. The stimulation of the choline/Mg 2+ antiport by mefloquine, found in this study, and by trifluoperazine and fluvoxamine, reported previously [Ebel et al. Biochim Biophys Acta 2004; 1167: 132-40], was associated with CF 3 groups attached to the quinoline or benzene ring. The effect of mefloquine on choline/Mg 2+ antiport in vitro was not related to the antimalarial action of mefloquine in vivo. In rat erythrocytes, the choline/Mg 2+ antiport can be differentiated from the Na +/Mg 2+ antiport through the use of cinchonine that inhibited the choline/Mg 2+ antiport [Ebel et al. Biochim Biophys Acta 2002; 1559: 135-44], and mefloquine that stimulated the choline/Mg 2+ antiport, whereby the Na +/Mg 2+ antiport was not affected by either drug at proper concentrations. The Na +/Mg 2+ antiport and choline/Mg 2+ antiports behave as different molecular entities.