D-myo-Inositol-1,3,4-triphosphate (sodium salt)

The inositol phosphates play a critical role as small, soluble second messengers in transmission of cellular signals. D-myo-Inositol-1,3,4-triphosphate (Ins(1,3,4)-P3) is one of several different inositol oligophosphate isomers implicated in signal transduction. Ins(1,3,4)-P3 acts through the inhibition of Ins(3,4,5,6)-P4 kinase activity to increase the cellular level of Ins(3,4,5,6)-P4 and thus inhibit calcium-activated chloride channels. The levels of Ins(1,3,4)-P3 are in turn regulated by the levels of cytosolic free calcium. The receptor-mediated activation of phospholipase C (PLC) can be seen as the initiating event in this cascade, since PLC generates Ins(1,4,5)-P3 which releases calcium from intracellular storage reservoirs, leading to a dramatic but transient increase in the cytosolic concentration of free calcium.