Yao T, Andersson S, Thorén P
Brain Res. 1982 May 20;240(1):77-85. doi: 10.1016/0006-8993(82)90645-x.
The influence of a prolonged low frequency electrical stimulation of the somatic afferents on cardiovascular and sympathetic nerve activities was investigated in unanaesthetized spontaneously hypertensive rats (SHRs) and Wistar-Kyoto normotensive rats (WKRs). In SHR, an elevation of blood pressure, heart rate and splanchnic nerve outflow was elicited during a 30-min period of sciatic nerve stimulation. Following the cessation of the stimulation, depressor response and bradycardia slowly developed and lasted up to 12 h. Activation of the group III or A-delta afferent fibers was essential for this post-stimulatory response. The progressive depressor response and a parallelled reduction of the splanchnic nerve activity, reached their maxima at about 1 h after the termination of the sciatic stimulation. The magnitude of the post-stimulatory depressor response was correlated with the prestimulatory control blood pressure level. There were also behavioural changes accompanying the depressor response. The cardiovascular and the behavioural depression were immediately reversed by naloxone (10-15 mg/kg, i.v.). The post-stimulatory depressor response was still present after bilateral sino-aortic denervation, but was absent in animals anaesthetized with chloralose and urethane. Emotional stress produced by air-blowing on the animal resulted in pressor response and tachycardia during the period of the stressful stimulation, but there was no depressor response following the termination of air-blowing. These findings indicate a sympathetic and cardiovascular depression induced by a prolonged stimulation of the somatic group III or A-delta afferent fibers; its long duration and naloxone reversibility suggest the involvement of endorphins in the mechanism of this response. The physiological significance of the effects of the prolonged somatic afferent stimulation and its possible relations with acupuncture are discussed.
在未麻醉的自发性高血压大鼠（SHR）和Wistar-Kyoto正常血压大鼠（WKR）中，研究了躯体传入神经的长时间低频电刺激对心血管和交感神经活动的影响。在SHR中，坐骨神经刺激30分钟期间会引起血压、心率和内脏神经传出活动升高。刺激停止后，降压反应和心动过缓缓慢出现并持续长达12小时。Ⅲ类或A-δ传入纤维的激活对于这种刺激后反应至关重要。渐进性降压反应和内脏神经活动的平行降低在坐骨神经刺激终止后约1小时达到最大值。刺激后降压反应的幅度与刺激前对照血压水平相关。降压反应还伴有行为变化。纳洛酮（10-15mg/kg，静脉注射）可立即逆转心血管和行为抑制。双侧窦主动脉去神经支配后仍存在刺激后降压反应，但在水合氯醛和乌拉坦麻醉的动物中不存在。对动物吹气产生的情绪应激在应激刺激期间导致升压反应和心动过速，但吹气终止后没有降压反应。这些发现表明，长时间刺激躯体Ⅲ类或A-δ传入纤维可诱导交感神经和心血管抑制；其长时间持续和纳洛酮可逆性提示内啡肽参与了该反应机制。讨论了长时间躯体传入刺激作用的生理意义及其与针灸的可能关系。
