Role of Chemoreceptor Activation in Hemodynamic Responses to Electrical Stimulation of the Carotid Sinus in Conscious Rats.
Role of Chemoreceptor Activation in Hemodynamic Responses to Electrical Stimulation of the Carotid Sinus in Conscious Rats.
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DOI：
10.1161/hypertensionaha.115.05316
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发表时间：
2015-09
期刊：
影响因子：
--
通讯作者：
Salgado HC
中科院分区：
文献类型：
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作者：
Katayama PL;Castania JA;Dias DP;Patel KP;Fazan R Jr;Salgado HC
颈动脉电反射激活已被用于治疗顽固性高血压患者。据推测，在有意识的大鼠中，颈动脉气压和化学感受器的联合激活减弱了反射性低血压。将大鼠分为4组：1)对照组，右侧颈动脉化学感受器单侧去神经支配；2)化学受体去神经支配组，双侧结扎颈动脉体动脉；3)压力感受器去神经支配组，左侧颈动脉压力感受器和右侧颈动脉化学感受器单侧去神经支配；4)颈动脉分叉去神经组，左侧颈动脉压力感受器和化学感受器去神经，右侧颈动脉化学感受器去神经。实验动物接受4轮（5 V, 1 ms）， 15 Hz, 30 Hz， 60 Hz和90 Hz的随机电刺激，持续20 s。在60 Hz （- 37 mmHg vs - 19 mmHg）和90 Hz （- 33 mmHg vs - 19 mmHg）电刺激下，化学感受器去神经支配组的降压反应比对照组大。压力感受器去神经组在所有频率的刺激下均表现出高血压反应。相反，颈动脉窦去神经组没有血流动力学反应。对照组心率无变化，而化学感受器去神经支配组和压力感受器去神经支配组出现心动过缓反应。这些数据表明，颈动脉化学感受器的激活可以减弱由联合电刺激颈动脉窦和颈动脉窦神经引起的反射性低血压。这些发现可能为使用压力反射激活疗法治疗顽固性高血压和/或心力衰竭的临床研究提供有用的见解。
Electrical carotid baroreflex activation has been used to treat patients with resistant hypertension. It is hypothesized that, in conscious rats, combined activation of carotid baro- and chemoreceptors afferences attenuates the reflex hypotension. Rats were divided into 4 groups: 1) control group, with unilateral denervation of the right carotid chemoreceptors; 2) chemoreceptor denervation group, with bilateral ligation of the carotid body artery; 3) baroreceptor denervation group, with unilateral denervation of the left carotid baroreceptors and right carotid chemoreceptors; 4) carotid bifurcation denervation group, with denervation of the left carotid baroreceptors and chemoreceptors, plus denervation of the right carotid chemoreceptors. Animals were subjected to 4 rounds of electrical stimulation (5 V, 1 ms), with 15 Hz, 30 Hz, 60 Hz, and 90 Hz applied randomly for 20 s. Electrical stimulation caused greater hypotensive responses in the chemoreceptor denervation group than in the control group, at 60 Hz (−37 mmHg vs −19 mmHg) and 90 Hz (−33 mmHg vs −19 mmHg). The baroreceptor denervation group showed hypertensive responses at all frequencies of stimulation. In contrast, the carotid sinus denervation group showed no hemodynamic responses. The control group presented no changes in heart rate, whereas the chemoreceptor denervation group and the baroreceptor denervation group showed bradycardic responses. These data demonstrate that carotid chemoreceptor activation attenuates the reflex hypotension caused by combined electrical stimulation of the carotid sinus and the carotid sinus nerve in conscious rats. These findings may provide useful insight for clinical studies using Baroreflex Activation Therapy in resistant hypertension and/or heart failure.