Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center Research Institute, Osaka 565-8565, Japan.
Life Sci. 2011 Sep 26;89(13-14):498-503. doi: 10.1016/j.lfs.2011.07.026. Epub 2011 Aug 9.
To examine whether moderate efferent vagal nerve stimulation (VNS) attenuates the carotid sinus baroreflex-mediated arterial pressure (AP) regulation via its antagonism to the sympathetic system.
Carotid sinus baroreceptor regions were isolated from the systemic circulation in eight anesthetized and vagotomized rats. A staircase-wise input was imposed on carotid sinus pressure (CSP) with or without efferent VNS (20Hz, 2ms, 1-4V), while the responses in AP, heart rate (HR), and splanchnic sympathetic nerve activity (SNA) were measured.
A multiple linear regression analysis indicated that VNS decreased the minimum HR in the CSP-HR relationship by 58.2±4.9 beats/min (P<0.01) from its reference value of 387.0±5.8 beats/min. Although VNS significantly decreased an intercept of the SNA-AP relationship, it did not affect parameters of the CSP-AP relationship or the CSP-SNA relationship significantly. The operating-point AP of the baroreflex was decreased by 2.8±1.0mmHg (P<0.01) during VNS, which was less than 3% of the reference value of 117.7±1.2mmHg.
VNS, at an intensity of decreasing HR by approximately 13%, does not acutely attenuate the baroreflex-mediated sympathetic AP regulation.
研究中等强度传出迷走神经刺激（VNS）是否通过拮抗交感神经系统来减弱颈动脉窦压力感受器介导的动脉压（AP）调节。
在 8 只麻醉和迷走神经切断的大鼠中，将颈动脉窦压力感受器区域从体循环中分离出来。在施加传出 VNS（20Hz，2ms，1-4V）的情况下，对颈动脉窦压力（CSP）进行逐步输入，同时测量 AP、心率（HR）和内脏交感神经活动（SNA）的反应。
多元线性回归分析表明，VNS 使 CSP-HR 关系中的最小 HR 降低了 58.2±4.9 次/分（P<0.01），从参考值 387.0±5.8 次/分。尽管 VNS 显著降低了 SNA-AP 关系的截距，但它对 CSP-AP 关系或 CSP-SNA 关系的参数没有显著影响。在 VNS 期间，压力反射的工作点 AP 降低了 2.8±1.0mmHg（P<0.01），低于参考值 117.7±1.2mmHg 的 3%。
VNS 以降低 HR 约 13%的强度不会急性减弱压力感受器介导的交感 AP 调节。
