Following tyrosine phosphorylation and activation, PLCG1 dissociates from the VEGFR2 receptor and associates with its substrate phosphatidylinositol (4,5)-bisphosphate (PIP2) in the plasma membrane. PLCG1 hydrolyses PIP2 resulting in the generation of diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3). DAG is an activator of PKC which leads to subsequent activation of MAP kinase, resulting in increased endothelial cell proliferation. IP3 acts upon receptors in the endoplasmic reticulum causing release of intracellular calcium. Elevation of cytosolic Ca2+ stimulates eNOS to produce nitric oxide (NO) causing vascular dilation. Entry of extracellular calcium through specific channels is important for the activation of certain proteins (Takahashi et al. 2001, Takahashi et al. 1999, Xia et al. 1996).