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雌激素可阻断去卵巢大鼠迷走神经刺激后的心血管和自主神经变化。

Estrogen blocks the cardiovascular and autonomic changes following vagal stimulation in ovariectomized rats.

作者信息

Saleh T M, Saleh M C, Connell B J

机构信息

Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Canada.

出版信息

Auton Neurosci. 2001 Apr 12;88(1-2):25-35. doi: 10.1016/S1566-0702(01)00220-X.

Abstract

The current investigation examines the effect of acute and chronic estrogen administration on baroreflex sensitivity and autonomic tone following 2 h of vagal afferent stimulation in ovariectomized female rats. Female Sprague-Dawley rats were ovariectomized and supplemented daily for 7 days with either estrogen (OVX-E2; 0.5 microg/kg; s.c.) or saline (OVX-S; 0.9%; s.c.). On the 8th day the animals were anaesthetized (sodium thiobutabarbitol; 100 mg/kg) and instrumented for recording blood pressure, heart rate and efferent vagal and renal nerve activities. The baroreflex was evoked using intravenous injection of various doses of phenylephrine hydrochloride (0.025, 0.05+/-0.1 mg/kg). Electrical stimulation of vagal afferents for 2 h produces autonomic imbalance characterized by sympathoexcitation and parasympathetic withdrawal. This protocol of vagal stimulation produced a significant increase in renal nerve activity (from 20+/-6 to 140+/-20 spikes/2 s) and decreases in both vagal nerve activity (from 22+/-3 to 10+/-2 spikes/2 s) and baroreflex sensitivity (from 0.55+/-0.05 to 0.3+/-0.05) in OVX-S female rats. However. vagal stimulation had no effect on baroreflex sensitivity or autonomic nerve activities in OVX-E2 rats. Administration of a single, bolus dose of estrogen (1 x 10(-2) mg/kg) to OVX-S rats immediately prior to termination of vagal stimulation blocked the changes in autonomic nerve activities and baroreflex sensitivity previously observed. These results suggest that both chronic and acute estrogen supplementation may provide resistance to the autonomic disturbances associated with visceral afferent activation.

摘要

本研究考察了在切除卵巢的雌性大鼠中,急性和慢性给予雌激素对迷走神经传入刺激2小时后的压力反射敏感性和自主神经张力的影响。将雌性Sprague-Dawley大鼠切除卵巢,并连续7天每天补充雌激素(OVX-E2;0.5微克/千克;皮下注射)或生理盐水(OVX-S;0.9%;皮下注射)。在第8天,将动物麻醉(硫喷妥钠;100毫克/千克)并进行仪器安装,以记录血压、心率以及传出迷走神经和肾神经活动。通过静脉注射不同剂量的盐酸去氧肾上腺素(0.025、0.05±0.1毫克/千克)诱发压力反射。对迷走神经传入进行2小时的电刺激会产生以交感神经兴奋和副交感神经撤离为特征的自主神经失衡状态。这种迷走神经刺激方案使OVX-S雌性大鼠的肾神经活动显著增加(从20±6增加到140±20个峰/2秒),迷走神经活动(从22±3减少到10±2个峰/2秒)和压力反射敏感性(从0.55±0.05降低到0.3±0.05)均降低。然而,迷走神经刺激对OVX-E2大鼠的压力反射敏感性或自主神经活动没有影响。在迷走神经刺激即将结束前,给OVX-S大鼠单次推注一剂雌激素(1×10⁻²毫克/千克),可阻断先前观察到的自主神经活动和压力反射敏感性的变化。这些结果表明,慢性和急性补充雌激素均可抵抗与内脏传入激活相关的自主神经紊乱。

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