NOS3 and Hypertension: Considering that the neuronal nitric oxide synthase- (nNOS-) deficient mouse exhibits tachycardia primarily due to abnormal cardiac autonomic control [34] and that endothelial nitric oxide synthase (eNOS) gene therapy restores the basal HR in 2K1C mice [7], it is possible that nitric oxide (NO) plays a role in the autonomic control of HR in this model of RAS-dependent hypertension.