Multiple mechanisms may account for endothelial dysfunction in response to chronic nitrate therapy (Munzel et al, 2013; Munzel et al, 2011) and traffic noise exposure (Munzel et al, 2021; Munzel et al, 2018a), comprising modulation of the activity and/or expression of eNOS, reduced sensitivity of vascular smooth muscle cells to •NO, or more pronounced scavenging of •NO via its reaction with •O2−. The gene discussed is NOS3; the disease is endothelial dysfunction.