Minson C T, Halliwill J R, Young T M, Joyner M J
Department of Anesthesiology and General Clinical Research Center, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
Circulation. 2000 Feb 29;101(8):862-8. doi: 10.1161/01.cir.101.8.862.
Our goal was to test sympathetic and cardiovagal baroreflex sensitivity and the transduction of sympathetic traffic into vascular resistance during the early follicular (EF) and midluteal (ML) phases of the menstrual cycle.
Sympathetic baroreflex sensitivity was assessed by lowering and raising blood pressure with intravenous bolus doses of sodium nitroprusside and phenylephrine. It was defined as the slope relating muscle sympathetic nerve activity (MSNA; determined by microneurography) and diastolic blood pressure. Cardiovagal baroreflex sensitivity was defined as the slope relating R-R interval and systolic blood pressure. Vascular transduction was evaluated during ischemic handgrip exercise and postexercise ischemia, and it was defined as the slope relating MSNA and calf vascular resistance (determined by plethysmography). Resting MSNA (EF, 1170+/-151 U/min; ML, 2252+/-251 U/min; P<0.001) and plasma norepinephrine levels (EF, 240+/-21 pg/mL; ML, 294+/-25 pg/mL; P=0. 025) were significantly higher in the ML than in the EF phase. Furthermore, sympathetic baroreflex sensitivity was greater during the ML than the EF phase in every subject (MSNA/diastolic blood pressure slopes: EF, -4.15; FL, -5.42; P=0.005). No significant differences in cardiovagal baroreflex sensitivity or vascular transduction were observed.
The present study suggests that the hormonal fluctuations that occur during the normal menstrual cycle may alter sympathetic outflow but not the transduction of sympathetic activity into vascular resistance.
我们的目标是测试月经周期卵泡早期（EF）和黄体中期（ML）期间交感神经和心血管迷走神经压力反射敏感性，以及交感神经活动向血管阻力的传导。
通过静脉推注硝普钠和去氧肾上腺素降低和升高血压来评估交感神经压力反射敏感性。它被定义为肌肉交感神经活动（MSNA；通过微神经ography测定）与舒张压之间的斜率。心血管迷走神经压力反射敏感性被定义为R-R间期与收缩压之间的斜率。在缺血性手握运动和运动后缺血期间评估血管传导，它被定义为MSNA与小腿血管阻力（通过体积描记法测定）之间的斜率。静息MSNA（EF，1170±151 U/分钟；ML，2252±251 U/分钟；P<0.001）和血浆去甲肾上腺素水平（EF，240±21 pg/mL；ML，294±25 pg/mL；P = 0.025）在ML期显著高于EF期。此外，在每个受试者中，ML期的交感神经压力反射敏感性高于EF期（MSNA/舒张压斜率：EF，-4.15；FL，-5.42；P = 0.005）。未观察到心血管迷走神经压力反射敏感性或血管传导的显著差异。
本研究表明，正常月经周期中发生的激素波动可能会改变交感神经输出，但不会改变交感神经活动向血管阻力的传导。
