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in·o·si·tol 1,4,5-·tris·phos·phate (IP3),
a second messenger formed from phosphatidylinositol 4,5-bisphosphate; triggers the release of calcium ions from special vesicles of the endoplasmic reticulum; has a role in the activation of neutrophils.
a cyclic sugar alcohol, C6H12O6; usually referring to the most abundant isomer, myo-inositol, which is found in many plant and animal tissues.
intracellular second messenger released from phosphatidyl 4,5-bisphosphate in response to agonist-dependent, GTP-G protein-activated phospholipase C. Called also IP3. Causes release of Ca2+ from intracellular stores, thereby activating calmodulin.