Recently, we demonstrated in endothelial nitric oxide synthase deficient (eNOS−/−) mice that loss of endothelial NO led to increased protein levels of amyloid-β protein precursor (AβPP), β-site AβPP cleaving enzyme 1 (BACE1), and amyloid-β (Aβ) peptide. Therefore, our aim was to determine if NO supplementation in vivo would attenuate AβPP and BACE1 protein levels. cGMP levels were significantly increased while AβPP and BACE1 protein levels were statistically lower in cerebral microvessels from nitroglycerin-treated eNOS−/− mice as compared to vehicle-treated mice. Our findings support the concept that preservation of NO/cGMP signaling is an important modulator of expression and processing of AβPP.