alpha-Adrenergic control of blood flow during exercise: effect of sex and menstrual phase

作者:Limberg Jacqueline K; Eldridge Marlowe W; Proctor Lester T; Sebranek Joshua J; Schrage William G*
来源:Journal of Applied Physiology, 2010, 109(5): 1360-1368.
DOI:10.1152/japplphysiol.00518.2010

摘要

Sex differences exist in autonomic control of the cardiovascular system. This study was designed to directly test sex or female menstrual phase-related differences in alpha-adrenergic control of blood flow during exercise. We hypothesized that women would exhibit reduced alpha-adrenergic vasoconstriction compared with men during exercise; in addition, women would constrict less during the early luteal than the early follicular phase of the female menses. Young men (n = 10) were studied once and women (n = 9) studied twice, once during the early follicular phase and once during the early luteal phase of female menses. We measured forearm blood flow (FBF; Doppler ultrasound of the brachial artery) during rest and steady-state dynamic exercise (15 and 30% of maximal voluntary contraction, 20 contractions/min). A brachial artery catheter was inserted for the local administration of alpha-adrenergic agonists [phenylephrine (PE; alpha(1)) or clonidine (CL; alpha(2))]. Blood flow responses to exercise [forearm vascular conductance (FVC)] were similar between all groups. At rest, infusion of PE or CL decreased FVC in all groups (40-60% reduction). Vasoconstriction to PE was abolished in all groups at 15 and 30% exercise intensity. Vasoconstriction to CL was reduced at 15% and abolished at 30% intensity in all groups; women had less CL-induced constriction during the early luteal than early follicular phase (P < 0.017, 15% intensity). These results indicate that vasodilator responses to forearm exercise are comparable between men and women and are achieved through similar paths of alpha-adrenergic vascular control at moderate intensities; this control may differ at low intensities specific to the female menstrual phase.

  • 出版日期2010-11