Simvastatin inhibits acidic extracellular pH-activated, outward rectifying chloride currents in RAW264.7 monocytic-macrophage and human peripheral monocytes

Extracellular acidic pH activated chloride channels (ICl,acid) have been characterized in HEK 293 cells and mammalian cardiac myocytes. This study was designed to evaluate the expression of ICl,acid in RAW264.7 monocytic-macrophage and human peripheral monocytes and to investigate the effect of simvastatin on ICl,acid. In two kinds of cells, the activation and deactivation of the current rapidly and repeatedly followed the change of the extracellular solution to pH = 4.3. Compared with the outward current (pA/pF) activated at pH 4.3, the currents inhibited by simvastatin at concentrations of 0.1 μM were all decreased a little, however the currents at concentrations of 1 μM and 10 μM simvastatin were decreased significantly. The IC50 for simvastatin inhibiting ICl,acid of RAW264.7 was 13.77 μM. In summary, we report for the first time that simvastatin inhibits the ICl,acid of RAW264.7 monocytic-macrophage and human peripheral monocytes in a concentration-dependent manner.