Stimulation of choline/Mg antiport in rat erythrocytes by mefloquine

In non Mg-loaded and non malaria-infected rat erythrocytes, mefloquine (100 lmol·l) stimulated choline/Mg antiport without affecting the Na/Mg antiport. The stimulation of the choline/Mg 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 CF3 groups attached to the quinoline or benzene ring. The effect of mefloquine on choline/Mg antiport in vitro was not related to the antimalarial action of mefloquine in vivo. In rat erythrocytes, the choline/Mg antiport can be differentiated from the Na/Mg antiport through the use of cinchonine that inhibited the choline/Mg antiport [Ebel et al. Biochim Biophys Acta 2002; 1559: 135-44], and mefloquine that stimulated the choline/Mg antiport, whereby the Na/Mg antiport was not affected by either drug at proper concentrations. The Na/Mg antiport and choline/Mg antiports behave as different molecular entities.