Abstract:
Acid peptic disorders are the result from either excessive gastric acid secretion or
diminished mucosal defense that affects millions people worldwide. The most effective
therapeutic agents for these disorders is proton pump inhibitors (PPIs), which are the fifth bestselling drug that has been taken by millions of chronic users worldwide. However, since 2006, there is a growing body of evidence indicating that omeprazole, a PPIs, induced hypomagnesemia is a serious side effect of PPIs in chronic users. The mechanism of PPIs induced systemic Mg2+ deficit is currently unclear. The present study aimed to elucidate the direct effect long-term omeprazole administrations in rats. Our result showed omeprazole significantly suppressed plasma Mg2+ level and urinary Mg2+ excretion. Thus, omeprazole induced hypomagnesemia in rats. By using Ussing chamber techniques, it was shown that omeprazole markedly suppressed paracellular and transcellular Mg2+ absorptions. However, ASIC1a, OGR1, and P2Y purinoceptors had no contribution on the regulation of intestinal Mg2+ absorptions in rats. Omeprazole decreased Isc and paracellular cation selectivity and increased TER, thus, its suppressed intestinal paracellular permeability. Histological study revealed that omeprazole suppressed intestinal absorptive surface area and tight junction width. Therefore, omeprazole suppressed intestinal absorption, the mechanism of which still elusive. However, our results showed the compensatory mechanism in rat intestine by upregulation of TRPM6 and CNNM4 expression throughout intestinal tract. The underlying mechanism of this compensatory mechanism is unknown