In this regard, we have recently shown that mental stress–induced vasodilatation in the forearm, a response shown to be mediated at least in part by local nNOS-derived NO, is impaired in many patients with hypertension.27 Another clinical scenario in which the impact of nNOS dysfunction merits investigation is chronic heart failure, which is characterized by a significant increase in SVR. The gene discussed is NOS1; the disease is hypertensive disorder.