在尾核痛反应神经元和整体甩尾反射水平上研究CCK-8对抗电针的镇痛作用

Study on antagonism of CCK-8 to the analgesic effect of electroacupuncture at the levels of pain-related neurons in caudate nucleus and whole tail-flick reflex

目的研究八肽胆囊收缩素(CCK-8)对抗电针(EA)对大鼠尾核(Cd)中痛反应神经元放电和甩尾潜伏期(TFL)痛阈的同时影响。方法采用同步记录大鼠Cd中痛兴奋神经元(PEN)或痛抑制神经元(PIN)电变化与辐射热照大鼠尾所引起TFL的方法。结果(1)辐射热照大鼠尾可使PEN诱发放电增加或PIN诱发放电减少的同时发生甩尾反射,表现出辐射热致疼痛效应。(2)EA双侧“足三里”15min,可抑制PEN的电活动或加强PIN的电活动,同时使TFL延长,即呈现出EA的镇痛效应。(3)脑室(icv)注射CCK-8(10ng/10μl)能同时对抗EA所引起的PEN或PIN和TFL的镇痛作用。结论CCK-8的抗EA镇痛作用,在中枢痛反应神经元电活动和整体行为反射水平上是协调一致的。揭示,PEN和PIN的电活动作为疼痛和镇痛指标是确实可行的。

Objective To study the simultaneous antagonism of cholecystokinin octapeptide （CCK-8） to the effects of electroacupuncture （EA） on the discharges of pain-related neurons in caudate nucleus （ Cd ） and the painful threshold measured by tail-flick latency （TFL） in rats. Methods The electrical changes of pain-excited neurons （PEN） or pain- inhibited neurons （PIN） in Cd and TFL which caused by radiant heat focused on the tail of rats were recorded simultaneously. Results （ 1 ） The radiant heat focused on the tail of the rat simultaneously caused an increase in the evoked discharge of PEN or a reduction in the evoked discharge of PIN and the tail-flick reflex, showing the painful effect of radiant heat. （2） EA at bilateral “Zusanli”for 15 min resulted in an inhibition of the electrical activity of PEN as well as a potentiation of the electrical activity of PIN and a prolongation of TFL, i.e. exhibiting the analgesic effect of EA. （3） The analgesic effect of EA on PEN or PIN and TFL were simultaneously antagonized by intracebroventricular （icy） injection of CCK-8 （10 ng/ 10μl）. Conclusion The antagonism of CCK-8 to analgesic effect of EA shows the coordinative and consistent activities on the levels of the electrical activities of central pain-related neurons and the whole behaviour reflex. It suggests that the electrical activity of PEN and PIN as the markers of pain and analgesia are indeed feasible.