Dain W Jacob, Brian Shariffi, Braden J Bond, Natasha G Boyes, Samuel A Martin, Anna M Gonsalves, Jennifer L Harper, Brian P Bostick, Jacqueline K Limberg
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引用次数: 0
Abstract
β-Adrenergic receptors (ARs) mediate a portion of hypoxic vasodilation and blunt sympathetic vasoconstriction at rest. Vascular β-AR sensitivity may be greater in females relative to males; however, their sex-specific role during hypoxia has yet to be examined. We hypothesized β-AR blockade would blunt hypoxic vasodilation and augment sympathetic vasoconstriction during hypoxia, with effects greater in females relative to males. Ten female (26 ± 8 yr, 23 ± 3 kg/m2) and 13 male (28 ± 7 yr, 25 ± 2 kg/m2) adults completed two study visits randomized and blinded to oral placebo or propranolol (β-AR blockade; 1 mg/kg) (NCT05256069). Forearm blood flow (FBF, venous occlusion plethysmography) and blood pressure (BP, finger photoplethysmography) were assessed for 10-min normoxic rest, followed by 5 min of steady-state hypoxia (∼80% [Formula: see text]). Sympathetic activation was achieved via a cold pressor test (CPT) conducted during normoxia and steady-state hypoxia. FBF was normalized for mean BP (forearm vascular conductance, FVC). Absolute (Δ) and relative (%) changes in FVC in response to hypoxia and CPT were calculated. β-AR blockade significantly reduced hypoxic vasodilation in females but not in males (interaction of hypoxia and sex: ΔFVC P = 0.029, %FVC P = 0.030). Sympathetic vasoconstriction was attenuated during hypoxia in females compared with males (main effect of sex: ΔFVC P = 0.005, %FVC P = 0.015), but there was no effect of β-AR blockade in either sex (main effect of drug: ΔFVC P = 0.406; %FVC P = 0.238; interaction of drug and sex: ΔFVC P = 0.619, %FVC P = 0.390). β-Adrenergic receptors mediate hypoxic dilation in females but not in males and do not restrain sympathetic-mediated vasoconstriction during hypoxia in either sex.NEW & NOTEWORTHY β-Adrenergic receptors contribute to hypoxic vasodilation, attenuate sympathetic vasoconstriction at rest, and are more sensitive in females versus males. We hypothesized β-adrenergic receptor blockade would blunt hypoxic vasodilation and augment the sympathetic vasoconstriction during hypoxia, with effects greater in females relative to males. Present data demonstrate β-adrenergic receptors contribute to hypoxic vasodilation in females but do not restrain sympathetic-mediated vasoconstriction during hypoxia in either sex.
期刊介绍:
The American Journal of Physiology-Heart and Circulatory Physiology publishes original investigations, reviews and perspectives on the physiology of the heart, vasculature, and lymphatics. These articles include experimental and theoretical studies of cardiovascular function at all levels of organization ranging from the intact and integrative animal and organ function to the cellular, subcellular, and molecular levels. The journal embraces new descriptions of these functions and their control systems, as well as their basis in biochemistry, biophysics, genetics, and cell biology. Preference is given to research that provides significant new mechanistic physiological insights that determine the performance of the normal and abnormal heart and circulation.