NOS3 and endothelial dysfunction: Substantial evidences have shown that endothelial dysfunction characterized by down-regulated activity of endothelial nitric oxide synthase (eNOS) is critically involved in vascular dysfunction in hypertension (Panza et al., 1993; Vanhoutte, 1996; Higashi et al., 2012; Nguyen et al., 2013; Yannoutsos et al., 2014).