Disorders of eNOS expression and activity are combined with disease entities such as atherosclerosis , coronary heart disease , hypercholesterolemia and hypertension . The first time was identified eNOS in endothelial cells of veins and arteries ; More detailed studies have shown the presence of this enzyme in myocytes , platelets, and neurons Leydig and Sertoli cells . Endothelial nitric oxide synthase accumulates inwaginacji at specific sites of the cell membrane . It is postulated that the depressions of the cell membrane provides a central location (the microdomains ) in the transduction of signals from outside the cell . Endothelial nitric oxide synthase in an inactive form closely interact with caveolin - 1 , a protein belonging to the relatively large family of transmembrane proteins . The main receptor for nitric oxide , irrespective of the source and nature of tissue formed within which is soluble guanylate cyclase . The result is an increase in the activation of adenylate cGMP level necessary to activate protein kinase G ( PKG ) . Because of the extremely wide range of substrates PKG eNOS activation leads to a differentiated response , dependent on the type of cell. Within endothelial nitric oxide plays a crucial role in the local regulation of blood pressure and inhibits the aggregation and platelet adhesion , and modulates cardiac myocyte contractile activity . It was shown that functional eNOS is necessary in the process of angiogenesis and vascular remodeling . Due to the free radical nature of NO, which is an excessive level of danger to the surrounding cells , eNOS activity is subject to strict and complex regulations . The most basic element of this control is the activation of protein determined by binding of the complex Ca 2 + / calmodulin . Additional elements of this regulation and phosphorylation of the enzyme depalmitylacja and association with heat shock protein Hsp90 . Despite the recognition of the constitutive enzyme eNOS , in the past few years demonstrated that gene expression is subject to fluctuations in response to growth factors , hormones , cytokines, and physical factors . Already carried out experiments do not allow definitive conclusion on the proposed role of endothelial nitric oxide synthase in a number of diseases of the circulatory system .