Menstrual cycle and sex effects on sympathetic responses to acute chemoreflex stress
Menstrual cycle and sex effects on sympathetic responses to acute chemoreflex stress
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DOI：
10.1152/ajpheart.00345.2014
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发表时间：
2015-03-15
影响因子：
4.8
通讯作者：
Shoemaker, J. Kevin
中科院分区：
文献类型：
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作者：
Usselman, Charlotte W.;Gimon, Tamara I.;Shoemaker, J. Kevin
本研究旨在研究性别(男性与女性)和性激素(女性的月经周期阶段)对年轻健康个体对强烈化学反射激活的交感反应的影响。肌交感神经活动(MSNA)在基线和重复呼吸时被测量，然后是最大吸气末呼吸暂停。在女性中，月经周期的黄体中期(ML)的基线MSNA大于卵泡早期(EF)。基线MSNA突发发生率男性高于女性，而突发频率和总MSNA仅在ML期在男性和女性之间相似。在所有参与者中，化学感受性反射的激活引起MSNA突发频率、幅度和总活动度的逐渐增加。在女性中，这种交感兴奋在EF期比ML期更强。女性对化学反射刺激EF时相的交感兴奋反应也大于男性。尽管如此，总外周阻力的变化在性别和月经周期阶段之间是相似的。这表明，在化学反射激活的EF阶段，神经血管转导被减弱，从而抵消了夸大的交感兴奋。化学反射引起的平均动脉压升高在不同性别和月经周期阶段都是相似的。在急性化学反射刺激期间，神经血管转导的减少可以提供一种机制，通过这种机制，女性相对于男性可能会减少与呼吸暂停相关的发病率。
This study aimed to examine the effects of sex (males vs. females) and sex hormones (menstrual cycle phases in women) on sympathetic responsiveness to severe chemoreflex activation in young, healthy individuals. Muscle sympathetic nerve activity (MSNA) was measured at baseline and during rebreathing followed by a maximal end-inspiratory apnea. In women, baseline MSNA was greater in the midluteal (ML) than early-follicular (EF) phase of the menstrual cycle. Baseline MSNA burst incidence was greater in men than women, while burst frequency and total MSNA were similar between men and women only in the ML phase. Chemoreflex activation evoked graded increases in MSNA burst frequency, amplitude, and total activity in all participants. In women, this sympathoexcitation was greater in the EF than ML phase. The sympathoexcitatory response to chemoreflex stimulation of the EF phase in women was also greater than in men. Nonetheless, changes in total peripheral resistance were similar between sexes and menstrual cycle phases. This indicates that neurovascular transduction was attenuated during the EF phase during chemoreflex activation, thereby offsetting the exaggerated sympathoexcitation. Chemoreflex-induced increases in mean arterial pressure were similar across sexes and menstrual cycle phases. During acute chemoreflex stimulation, reduced neurovascular transduction could provide a mechanism by which apnea-associated morbidity might be attenuated in women relative to men.