Source:http://linkedlifedata.com/resource/umls/id/C0021549
MSH: Intracellular messenger formed by the action of phospholipase C on phosphatidylinositol 4,5-bisphosphate, which is one of the phospholipids that make up the cell membrane. Inositol 1,4,5-trisphosphate is released into the cytoplasm where it releases calcium ions from internal stores within the cell's endoplasmic reticulum. These calcium ions stimulate the activity of B kinase or calmodulin.,NCI: A phosphatidylinositol with phosphate covalently bound in the 4 and 5 positions of the inositol group. Inositol 1,4,5-trisphosphate acts as an intermediate in the IP3/DAG pathway, hydrolyzed by phospholipase C and liberating diacylglycerol and PIP2, which activate Protein Kinase C and calcium release from the endoplasmic reticulum, respectively.