Sphingosine-1-phosphate (S1P) acts on a set of G protein-coupled receptors in the plasma membrane and also as a second messenger in certain cell types.There are two possible pathways to mobilize intracellular Ca2+ concentration by S1P.One is through phospholipase C, SOD and the other is through intracellular Ca2+ channels operated by S1P.The Mn2+ quenching method was applied to elucidate the action mode of S1P-induced Ca2+ mobilization in rat hepatocytes.
In Keyboards permeabilized hepatocytes, inositol trisphosphate induced Mn2+ quenching, and it was blocked by heparin.However, S1P did not induce Mn2+ quenching.Results suggest that S1P did not mobilize Ca2+ through intracellular Ca2+ channels.Keywords:: hepatocyte, sphingosine 1-phosphate, second messenger.