He X R, Wang W, Crofton J T, Share L
Department of Physiology, University of Tennessee, Memphis, Memphis, Tennessee 38163, USA.
Am J Physiol. 1999 Aug;277(2):R493-8. doi: 10.1152/ajpregu.1999.277.2.R493.
The effects of chronic treatment with 17beta-estradiol on baroreflex control of sympathetic activity were examined in conscious unrestrained ovariectomized rats. Baroreflex function was evaluated by logistic sigmoidal analysis of the relationships between changes in mean arterial pressure (MABP) and changes in heart rate (HR) and splanchnic nerve activity (SNA) when MABP was rapidly increased to 150 mmHg by intravenous phenylephrine after its reduction to 50 mmHg by intravenous nitroprusside. These baroreflex function curves were similar in vehicle- and estradiol-treated rats. However, after a 30-min infusion of vasopressin in vehicle-treated rats, the curve for HR was shifted downward, and the upper plateau and maximum gain for the SNA curve were reduced. These effects were abolished by estradiol. A 30-min phenylephrine infusion had no effect on the baroreflex curves. Thus estrogen can modulate the action of vasopressin on baroreflex control of sympathetic outflow and thereby participate in cardiovascular regulation.
在清醒自由活动的去卵巢大鼠中，研究了17β-雌二醇长期治疗对压力反射控制交感神经活动的影响。通过对平均动脉压（MABP）变化与心率（HR）和内脏神经活动（SNA）变化之间关系进行逻辑S形分析来评估压力反射功能，即先通过静脉注射硝普钠将MABP降至50 mmHg，然后通过静脉注射去氧肾上腺素将MABP迅速升至150 mmHg。在给予载体和雌二醇治疗的大鼠中，这些压力反射功能曲线相似。然而，在给予载体治疗的大鼠中静脉输注血管加压素30分钟后，HR曲线向下移动，SNA曲线的上平台期和最大增益降低。这些作用被雌二醇消除。静脉输注去氧肾上腺素30分钟对压力反射曲线无影响。因此，雌激素可调节血管加压素对交感神经传出活动的压力反射控制作用，从而参与心血管调节。
