Excitation of baroreceptors depresses A- and C-components of the somato-cardiac sympathetic reflex in anesthetized rats
Excitation of baroreceptors depresses A- and C-components of the somato-cardiac sympathetic reflex in anesthetized rats
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DOI：
10.2170/jjphysiol.48.261
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发表时间：
1998-08-01
期刊：
影响因子：
--
通讯作者：
Sato, A
中科院分区：
文献类型：
--
作者：
Li, WM;Liu, X;Sato, A
在乌拉坦麻醉、迷走神经切断和人工呼吸的大鼠上，观察了压力感受器兴奋对体心交感神经反射放电的影响。单次电击刺激左后肢胫神经有髓(A)和无髓(C)纤维，在心交感神经的一个分支引起两个独立的兴奋性反射放电成分，称为体心交感神经反射放电的A和C成分。当主动脉神经(AN)和颈动脉窦神经(CSN)完整时，静脉注射诱发平均动脉压突然升高至约150毫米汞柱。注射去甲肾上腺素(50mug/kg)后，A、C组分的抑制率分别为对照组的47+/-5.4%和37+/-7.7%。然而，双侧去正弦-主动脉神经完全取消了压力引起的这两种成分的抑制。我们的结论是，来自AN和CSN的压力感受器传入信号抑制兴奋性躯体-心脏交感反射放电的A和C成分。这一证据和文本中提到的其他以前的证据表明，来自动脉压力感受器的抑制性交感反射和来自躯体传入的兴奋性交感反射相互作用，可能在脑干。
The effect of baroreceptor activation on somato-cardiac sympathetic reflex discharges was examined in urethane-anesthetized, vagotomized, and artificially ventilated rats. Single shock stimulation of myelinated (A) and unmyelinated (C) fibers in the tibial nerve of the left hindlimb elicited two separate excitatory reflex discharge components in a branch of the cardiac sympathetic nerve, They are termed the A- and C-components of the somato-cardiac sympathetic reflex discharges. When aortic nerves (AN) and carotid sinus nerves (CSN) were intact, a sudden increase in mean arterial blood pressure to about 150 mmHg induced by i.v. injection of phenylephrine (50 mu g/kg) depressed the A- and C-components by up to 47 +/- 5.4 and 37 +/- 7.7% of the control values, respectively. However, bilateral sine-aortic denervation completely abolished the pressure-induced depression of both components. We conclude that baroreceptor afferent signals from the AN and CSN inhibit both A- and C-components of the excitatory somato-cardiac sympathetic reflex discharges. This and other previous evidence mentioned in the text indicate that inhibitory cardiac sympathetic reflexes originating from arterial baroreceptors and excitatory ones originating from somatic afferents interact, probably at the brainstem.