电针“足三里”穴对大鼠迷走神经放电的影响

目的:观察电针大鼠双侧“足三里”穴对迷走神经放电的影响。方法:将30只健康成年SD雄性大鼠(200~240 g)随机分为对照组、足三里组(电针双侧“足三里”穴)和非经非穴组(电针非经非穴,即“足三里”穴外侧旁开5 mm处),每组10只。足三里组及非经非穴组大鼠以3 Hz脉冲电流持续进行电针刺激30 min,强度以双下肢微颤为宜(约2~4 V)。以双极铂电极分别引导左侧迷走神经传出及传入纤维,采用生物机能试验仪连续记录迷走神经放电频率和峰值。结果:刺激前后,对照组与非经非穴组大鼠迷走神经传出和传入纤维放电频率和峰值均无显著性改变(P>0.05);组内各时间点比较亦无显著性差异(P>0.05)。足三里组电刺激“足三里”穴(7.5±3.4)min后,迷走神经传出纤维放电频率明显加快,峰值增加,与刺激前比较差异均有显著性意义(P<0.01),各参数值均显著高于对照组和非经非穴组相应时间点(P<0.01);而传入纤维放电的各参数值均无明显改变。结论:电针“足三里”穴可以使迷走神经传出纤维放电增强,但对其传入纤维放电无影响。

Effect of Electroacupuncture at "Zusanli" (ST 36) on Vagal Electrical Activity in the Rat

Objective: To observe changes of vagal electrical activity after electroacupuncture(EA) at "Zusanli"(ST 36).Methods: Thirty male SD rats(220±20 g) were evenly and randomly divided into control group,EA group,and non-acupoint group.After anesthesia(20% urethane,1 g/kg,i.p.),the rat's bilateral cervical vagus nerves were isolated and ligated on the middle part;then,two pairs of bipolar platinum electrodes were respectively placed at the cephalic and caudal ends of the ligated site for recording the discharges of the afferent and efferent fibers of the vagus nerve(covered with mineral oil).The electrical signals from the electrodes were amplified,filtered(100-1000 Hz),and fed to a computer for recording and analysis.EA(3 Hz,2-4 V) was applied to bilateral "Zusanli"(ST 36) and non-acupoints(about 5 mm beside ST 36) for 30 min separately.Results: Both afferent and efferent vagal activity of control group and non-acupoint group had no apparent changes(P>0.05) during the experimental course.In EA group,about 7.5 min after EA of "Zusanli"(ST 36),both the frequency and the peak values of the efferent vagal electrical activity increased significantly in comparison with pre-stimulation(P<0.01).However,this situation did not happen in the afferent vagal activity.Conclusion: EA of "Zusanli"(ST 36) can increase the efferent activity of the vagal nerve,but does not influence the afferent activity.