D-myo-Inositol-1,4,6-phosphate (Ins(1,4,6)-P3) is a member of the inositol phosphate (InsP) family that play critical roles as small, soluble second messengers in the transmission of cellular signals. The most studied InsP, Ins(1,4,5)-P3, is a second messenger produced in cells by phospholipase C (PLC)-mediated hydrolysis of phosphatidylinositol-4,5-biphosphate. Binding of Ins(1,4,5)-P3 to its receptor on the endoplasmic reticulum results in opening of the calcium channels and an increase in intracellular calcium. Ins(1,4,6)-P3 (tested as the meso compound) is 9-fold less potent than Ins(1,4,5)-P3 at initiating Ca2+ release when injected into Xenopus oocytes.