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Isolated pharmacological vasodilation does not stimulate skeletal muscle protein synthesis in healthy older adults.
Author(s) -
Timmerman Kyle Lee,
Markofski Melissa M,
Dhanani Shaheen,
Fry Chris S,
Dickinson Jared M,
Walker Dillon K,
Gundermann David M,
Rasmussen Blake B,
Volpi Elena
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.233.7
Subject(s) - anabolism , skeletal muscle , endocrinology , medicine , vasodilation , insulin , concomitant , sodium nitroprusside , nitric oxide
Increases in blood flow and amino acid delivery are necessary for insulin to stimulate skeletal muscle protein anabolism in young and older subjects. In older adults, endothelial dysfunction results in blunted skeletal muscle vasodilation and protein synthesis in response to insulin and mixed feeding, which can be overcome by concomitant pharmacological vasodilation. The purpose of this study was to determine if pharmacological vasodilation alone, in the absence of a concomitant anabolic stimulus, can increase muscle protein synthesis and anabolism in healthy older adults. In 7 healthy older subjects we measured blood flow, anabolic signaling, and muscle protein turnover using stable isotope methodologies at baseline and during isolated sodium nitroprusside (SNP) infusion in one leg. Blood flow and phenylalanine delivery increased significantly during SNP infusion (P< 0.05), but there were no significant changes in mTOR and S6K1 activation, muscle protein synthesis or breakdown. There was a trend for phenylalanine net balance to decrease during SNP infusion (P=0.07). In conclusion, pharmacological increases in blood flow and amino acid delivery in the absence of a concomitant anabolic stimulus (insulin or nutrition) do not significantly stimulate skeletal muscle protein synthesis or anabolism in healthy older adults. Funded by NIH R01 AG018311 and P30 AG024832