PMID- 20637278 OWN - NLM STAT- MEDLINE DCOM- 20110203 LR - 20220317 IS - 1873-6815 (Electronic) IS - 0531-5565 (Linking) VI - 45 IP - 11 DP - 2010 Nov TI - Caloric restriction improves endothelial dysfunction during vascular aging: Effects on nitric oxide synthase isoforms and oxidative stress in rat aorta. PG - 848-55 LID - 10.1016/j.exger.2010.07.002 [doi] AB - Aging is characterized by activation of inducible over endothelial nitric oxide synthase (iNOS and eNOS), impaired antioxidant activity and increased oxidative stress, which reduces nitric oxide bioavailability and causes endothelial dysfunction. Caloric restriction (CR) blunts oxidative stress. We investigated whether CR impacts endothelial dysfunction in aging and the underlying mechanisms. Aortas from young (YC, 6 months of age) and old (OC, 24 months of age) rats ad-libitum fed and from old rats caloric-restricted for 3-weeks (OR, 26%) were investigated. Endothelium-dependent vasorelaxation was impaired in OC, associated with reduced eNOS and increased iNOS expression (P<0.05). Aortic nitrite was similar in OC and YC, but the contribution of calcium-independent NOS to total NOS activity was increased whereas that of calcium-dependent NOS was reduced (p