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ATP‐mediated vasodilation is not reduced in aging humans
Author(s) -
Kirby Brett Sean,
Voyles Wyatt F,
Crecelius Anne R,
Dinenno Frank A
Publication year - 2009
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.23.1_supplement.777.4
Subject(s) - vasodilation , medicine , sodium nitroprusside , endocrinology , adenosine , acetylcholine , forearm , plethysmograph , endothelium , adenosine triphosphate , nitric oxide , anatomy
Endothelium‐dependent vasodilation is reduced with age, as evidenced by blunted vasodilator responsiveness to acetylcholine (ACH) infusions. Circulating adenosine triphosphate (ATP) has been implicated in the control of skeletal muscle vascular tone during mismatches in oxygen delivery and demand (e.g., exercise) via binding to purinergic receptors on the endothelium, and aging is typically associated with reductions in muscle blood flow under such conditions. Therefore, we tested the hypothesis that ATP‐mediated vasodilation is impaired in aging humans and that ascorbic acid (AA) infusion would acutely restore this impairment. We measured forearm blood flow (FBF; venous occlusion plethysmography) responses to local intra‐arterial infusions of ACH, ATP, and sodium nitroprusside (SNP) with and without AA infusion in 13 young and 13 older adults. The peak increase in FBF to ACH was significantly impaired in older compared with younger adults (260±70% vs 620±99%; P<0.05), and this difference was abolished during AA infusion (520±80% vs 560±70%). Peak FBF responses were not different between older and young adults to either ATP (675±105% vs 735±125%) or SNP (1120±110% vs 1140±150%) and AA infusion did not alter these responses (both NS). Thus, in contrast to the observed impairments in ACH responses, the vasodilatory response to exogenous ATP is not reduced with age in healthy humans.