Na+/H+ antiporter is the primary proton transport system used by osteoclasts during bone resorption

Abstract
We have examined the effects of inhibitors of proton transport systems on osteoclastic bone resorption using an in vitro bone slice assay, where osteoclasts (OCs) are free from the influence of other bone cells. Amiloride (AM) and dimethyl‐amiloride (DMA), inhibitors of the Na+ /H+ antiporter, were potent inhibitors of bone resorption (IC50 ∼ 9 and 0.7 μM for AM and DMA, respectively). Omeprazole (OM), a potent inhibitor of parietal cell K+ /H+ ‐ATPase, was a poor inhibitor of OC bone resorption (IC50 ∼ 100 μM). These results strongly suggest that the Na+ /H+ antiporter is the primary proton system used by OCs during bone resorption.