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Short‐term hypercaloric diet induces blunted aortic vasoconstriction and enhanced vasorelaxation via increased nitric oxide synthase 3 activity and expression in D ahl salt‐sensitive rats
Author(s) -
Spradley F. T.,
Kang K.T.,
Pollock J. S.
Publication year - 2013
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/apha.12025
Subject(s) - nitric oxide synthase , nitric oxide , vasoconstriction , medicine , endocrinology , chemistry
Aim To elucidate the role of the O 2 ‐ , H 2 O 2 or NO pathways in aortic angiotensin (Ang) II ‐induced vasoconstriction in Dahl salt‐sensitive ( SS ) rats compared with control SS ‐13 BN rats on a normal or hypercaloric diet. Methods Aortic function was assessed using wire myography in 16‐week‐old rats maintained on a normal diet or a 4‐week hypercaloric diet. Nitric oxide synthase ( NOS ) activity and expression was determined by the conversion of radio‐labelled arginine to citrulline and Western blot analysis respectively. Results On normal diet, Ang II ‐induced vasoconstriction was greater in SS than SS ‐13 BN rats. Polyethylene glycol superoxide dismutase ( PEG ‐ SOD ) reduced the aortic Ang II response similarly in both strains on normal diet. Catalase blunted, whereas N ω ‐Nitro‐L‐arginine methyl ester (L‐ NAME ) did not affect the Ang II response in SS rats. In SS ‐13 BN rats, catalase had no effect and L‐ NAME enhanced Ang II response. On hypercaloric diet, aortic Ang II responsiveness was reduced in SS but unaltered in SS ‐13 BN rats compared with their normal diet counterparts. PEG ‐ SOD reduced the Ang II response in both rats on hypercaloric diet. Catalase treatment did not alter aortic Ang II response, while L‐ NAME increased the response in SS rats on hypercaloric diet. In SS ‐13 BN rats on hypercaloric diet, catalase reduced and L‐ NAME did not alter the Ang II response. Furthermore, aortic endothelial‐dependent vasorelaxation was increased in SS rats on hypercaloric diet compared with normal diet and aortic NOS 3 activity and expression was increased. Conclusion A short‐term hypercaloric diet induces a blunted vasoconstrictive and enhanced vasodilatory phenotype in SS rats, but not in SS ‐13 BN rats, via reduced H 2 O 2 and increased NOS 3 function.