He X R, Wang W, Crofton J T, Share L
Department of Physiology and Biophysics, University of Tennessee, Memphis, Tennessee 38163, USA.
Am J Physiol. 1998 Oct;275(4):R1202-8. doi: 10.1152/ajpregu.1998.275.4.R1202.
The effects of 17beta-estradiol (E2) on sympathetic activity were examined in conscious unrestrained ovariectomized rats, instrumented under methohexital anesthesia to record mean arterial pressure (MABP), heart rate (HR), renal nerve activity (RNA), and splanchnic nerve activity (SNA) 1 day before the experiment. Injection of E2 (150 micrograms/kg iv) caused reductions (P < 0.01) in RNA (29 +/- 6%), SNA (25 +/- 2%), and HR (26 +/- 5 beats/min) within 20 min, but MABP remained unchanged. Ninety minutes after intravenous injection of E2 or vehicle, intravenous infusion of phenylephrine (PE; 6.2 micrograms . min-1 . kg-1) induced similar increases in MABP and decreases in HR, RNA, and SNA in both groups. By contrast, in rats chronically treated with E2, the pressor response to PE was smaller (P < 0.01; 22 +/- 5 mmHg) than in vehicle-treated rats (40 +/- 4 mmHg). The changes in HR, RNA, and SNA were similar in both groups, but the ratios of changes in HR and SNA to MABP, an index of baroreflex sensitivity, were greater in the E2-treated rats. These findings suggest that E2 can act centrally to modulate sympathetic function 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（E2）对交感神经活动的影响。在实验前1天，大鼠在美索比妥麻醉下进行仪器植入，以记录平均动脉压（MABP）、心率（HR）、肾神经活动（RNA）和内脏神经活动（SNA）。静脉注射E2（150微克/千克）在20分钟内可使RNA（29±6%）、SNA（25±2%）和HR（26±5次/分钟）降低（P<0.01），但MABP保持不变。静脉注射E2或赋形剂90分钟后，两组静脉输注去氧肾上腺素（PE；6.2微克·分钟-1·千克-1）均引起MABP类似升高以及HR、RNA和SNA降低。相比之下，长期接受E2治疗的大鼠对PE的升压反应（P<0.01；22±5 mmHg）小于接受赋形剂治疗的大鼠（40±4 mmHg）。两组HR、RNA和SNA的变化相似，但E2治疗组大鼠HR和SNA变化与MABP的比值（压力反射敏感性指标）更大。这些发现表明，E2可通过中枢作用调节交感神经功能，从而参与心血管调节。
