各类传入纤维在不同条件下的电针镇痛作用及其机制的探讨

本研究以家兔反射性下颌运动为痛反应,观察了不同条件下各类传入纤维的电针镇痛作用并探讨其产生的可能机制。结果表明: 1.各类传入纤维在不同条件下的电针镇痛作用仍然是兴奋的纤维越细镇痛作用越强。 2:粗纤维 (Ⅰ、Ⅱ类纤维) 的作用具有明显的节段性特征;而细纤维 (Ⅲ、Ⅳ类纤维) 的作用是超节段性的,它主要是通过激活内源性吗啡样镇痛系统而发挥其镇痛作用的。 3.高频电针可明显减弱细纤维的传入活功,使Ⅲ类纤维的作用减弱或消失,Ⅳ类纤维的作用虽不减弱但有应激成分的参与,因而是不适用的。 4.我们建议:在针剌镇痛和针剌麻醉实践中采用近节段,低频率、高强度电针剌激有可能取得最满意的镇痛效果。

Electroacupuncture(EA) Analgesic Effects of Various Groupsof Afferent Fibers Under Different Conditions and Studies on Their Genetie Mechanisms

In this study, reflexive lower jaw movements were taken as pain response in the rahbits. EA analgesic effects of various groups of the afferent fibers were observed, under different conditions and their genetic mechanisms were studied. The results are as follows: a) EA analgesic effects of various groups of the afferent fibers still were that the smaller the excited fibers, the stronger the produced analgesic effects. b) The segmental characteristic was obviously indicated in analgesic effects of the large-diameter fibers, but those of the small-diameter fibers were hypersegmental and the effects were exerted by activating the endogenous morhpine-like analgesia systems. c) The afferent impulses of small-diameter fibers could be reduced by high-frequency EA stimulation, so that the analgesia produced by group Ⅲ fibers was impaired or disappeared, and, though the produced group Ⅳ fibers was not impaired, stressful response might partly participate in this analgesia. Thus, high-frequency EA stimulation is not convenient. d) We suggest that the best analgesic effects should be obtained by using near segment, low frequency and high intensity EA stimulation in the clinical practice of EA analgesia and anaesthesia.