The roles of acid-sensing ion channel 1a and ovarian cancer G protein-coupled receptor 1 on passive Mg2+ transport across intestinal epithelium-like Caco-2 monolayers

Abstract

Intestinal passive Mg2+ absorption, which is vital for normal Mg2+ homeostasis, has been shown to be regulated by luminal proton. We aimed to study the regulatory role of intestinal acid sensors in paracellular passive Mg2+ transport. Omeprazole enhanced the expressions of acid-sensing ion channel 1a (ASIC1a), ovarian cancer G protein-coupled receptor 1 (OGR1), and transient receptor potential vanilloid 4 in Caco-2 cells. It also inhibited passive Mg2+ transport across Caco-2 monolayers. The expression and activation of OGR1 resulted in the stimulation of passive Mg 2+ transport via phospholipase C- and protein kinase C-dependent pathways. ASIC1a activation, on the other hand, enhanced apical HCO3- secretion that led, at least in part, by a Ca2+- dependent pathway to an inhibition of paracellular Mg2+ absorption. Our results provided supporting evidence for the roles of OGR1 and ASIC1a in the regulation of intestinal passive Mg2+ absorption. © 2013 The Physiological Society of Japan and Springer Japan.