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Impaired hypoxic vasodilation in healthy older adults: role for altered sympatho‐adrenal control of vascular tone
Author(s) -
Richards Jennifer Clarke,
Crecelius Anne R.,
Kirby Brett S.,
Garcia Leora J.,
Luckasen Gary J.,
Larson Dennis G.,
Dinenno Frank A.
Publication year - 2013
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.27.1_supplement.1119.1
Subject(s) - vasodilation , medicine , brachial artery , hypoxia (environmental) , propranolol , vasoconstriction , blockade , adrenergic , endocrinology , cardiology , phentolamine , blood pressure , receptor , chemistry , organic chemistry , oxygen
We tested the hypothesis that peripheral vasodilation to graded systemic hypoxia (90, 85, 80% SaO 2 ) is impaired in older healthy adults due to attenuated β‐adrenergic mediated vasodilation and elevated α‐adrenergic vasoconstriction. Forearm blood flow was measured (Doppler ultrasound) and vascular conductance (FVC) was calculated in 12 young and 8 older adults to determine the dilatory response to hypoxia in control, local (brachial artery catheter) β‐blockade (propranolol), and combined α+β blockade (phentolamine+propranolol) conditions. Compared to young, older individuals exhibited impaired vasodilation to hypoxia (peak Δ+35±8% vs. +9±6 %ΔFVC P<0.05). Following β‐blockade, older adults actively constricted (−14±5%ΔFVC) whereas the young response was not significantly impacted. α+β blockade increased the dilatory response to hypoxia in both groups, however the dilatory response remained significantly greater in young compared with the old (+58±11% vs.+17±11%ΔFVC P<0.05). Our findings indicate that hypoxic vasodilation is significantly impaired in older adults and this can be attributed to lower β‐receptor mediated dilation, elevated α‐adrenergic constriction and lower local vasodilatory signaling. These findings may have implications for understanding regional blood flow control in aging patient populations that exhibit systemic and/or local hypoxia. Supported by HL102720