躯体-交感神经反射:一种可用于研究针刺原理的实验模型

电刺激麻醉大鼠的外周神经传入纤维 ,如胫神经 ,可诱发躯体 交感神经反射。这种反射电位可从交感神经传出纤维 ,如心脏或肾脏交感神经的分支中记录到。躯体 交感神经反射由两部分组成 :Ａ 反射 ,其传导延迟时间短 (41± 2ｍｓ) ,由刺激有髓传入纤维而诱发 ;Ｃ 反射 ,其传导延迟时间长 (2 1 0± 1 3ｍｓ) ,由刺激无髓传入纤维而诱发。一般认为 ,躯体 交感神经Ａ 反射和Ｃ 反射分别代表来自躯体外周的不同感觉传入信息成分。研究揭示麻醉大鼠的躯体 交感神经Ａ 和Ｃ 反射 ,不仅受一系列参与神经传导的活性物质 ,如谷氨酸和一氧化氮的调制 ,同…

Somato-sympathetic Reflexes: a Useful Experimental Model for Study on Acupuncture Mechanism

Electrical stimulation of afferent fibers of the tibial nerve in anaesthetiz ed rats evokes somato sympathetic reflexes which are recorded from efferent sym p athetic fibers such as branches of the inferior cardiac nerve or the renal nerve . The reflex sympathetic response consists of two components: A reflex, whi c h has a short latency (41±2 ms) and is elicited by stimulation of afferent myel inated fibers, and C reflex, which has a long latency (210±13 ms) and is a t tributed to unmyelinated afferent fibers. Generally speaking, the A and C ref lexes represent different somatic sensory inputs. Studies demonstrated that in anesthetized rats, the somato sympathetic A and C reflexes could be, respectively, modulated not only by several chemical agen ts involving neurotic transmission such as glutamate and nitric oxide, but al s o by sensory inputs from chemoreceptor or baroreceptor. Glutamate augmented, whi le nitric oxide inhibited the somato sympathetic A and C reflexes. Activatio n o f chemoreceptor augmented, while activation of baroreceptor inhibited the somato sympathetic A and C reflexes. In another study, an acupuncture needle (diam ete r 0.34 mm) was inserted into the hind limbs of the rat, dorsolaterally around th e area of acupoint: Huantiao (GB 30), at a depth of 4～5 mm and was twisted righ t and left ward twice every second during recording the somato sympathetic r efle xes. The study found that acupuncture inhibited both somato sympathetic A and C reflexes. These results suggest that the somato sympathetic reflexes may be an experimental model for study on acupuncture mechanism, because acupuncture, as a kind o f sensory input to the central nervous system, may has similar reflex pathways w hen it plays a therapeutic role in some target tissues and organs.