NOS3 and Hypertension: Another research showed that OPCs can increase the expression of endothelial NOS by activating adenosine-5′-monophosphate(5′-AMP) activated protein kinase (AMPK) and producing nitric oxide (NO) which can relieve hypertension by stretching blood vessels and eventually inhibiting the generation of high blood pressure in the hypertensive rats induced by Ouabain [98].