电针中脘穴对大鼠胃内酸刺激诱导的胃伤害性反应的影响及其机制研究

Effects and Mechanisms of Electroacupuncture at Zhongwan(CV12)on Gastric Nociceptive Response Induced by Gastric Acid Stimulation in Rats

目的观察电针中脘穴对胃内酸刺激诱导的胃伤害性反应的影响并探讨与延髓内脏感觉和内脏运动核团神经元相关的作用机制。方法20只SD大鼠均以0.5 mol/L稀盐酸0.5 ml/100 g灌胃以诱导胃伤害性反应,随机选出8只统计灌胃前1 min与灌胃后第1、5、10、15、20、25、30、35、40、45、50、55、60 min胃平滑肌肌电慢波信号(GSW)曲线下面积,以及延髓孤束核(NTS)和迷走神经背核(DMV)神经元细胞外放电频率;剩余12只大鼠于稀盐酸灌胃后5~25 min内给予中脘穴电针干预持续1 min,比较电针干预前后各1 min内GSW曲线下面积以及NTS和DMV神经元细胞外放电频率。结果与灌胃前比较,GSW曲线下面积在灌胃后第1、5、10、15、20、25 min明显增加,NTS兴奋性神经元(占比90%,57/63)细胞外放电频率在灌胃后第1、5、10、15、20、25、30、35、40 min明显升高,且均在灌胃后第1 min达到峰值(P<0.01或P<0.05);DMV抑制性神经元(占比91%,20/22)细胞外放电频率在灌胃后第1 min虽升高但差异无统计学意义(P>0.05),其余时间点均明显降低(P<0.05)。与中脘穴电针干预前比较,电针干预后GSW曲线下面积及NTS兴奋性神经元细胞外放电频率明显降低(P<0.05),而DMV抑制性神经元细胞外放电频率差异无统计学意义(P>0.05)。结论电针中脘穴可以改善胃内酸刺激诱导的胃伤害性反应,其可能通过减少内脏感觉的传入信息降低延髓NTS神经元的兴奋性而发挥作用。

Objective To observe the effects of electroacupuncture at Zhongwan(CV12)on gastric nociceptive response induced by gastric acid stimulation and explore the underlying mechanisms associated with nuclei of the medullary viscerosensory and visceral motor neurons.Methods Twenty SD rats were given intragastric administration of 0.5 mol/L diluted hydrochloric acid(0.5 ml/100 g)to induce gastric nociceptive response induction.Eight rats were randomly selected to record the gastric slow wave(GSW)area under the curve,and extracellular discharge frequency of neurons in the nucleus of the solitary tract(NTS)and dorsal motor nucleus of the vagus nerve(DMV)before intragastric administration and at 1,5,10,15,20,25,30,35,40,45,50,55,and 60 minutes after intragastric administration.The remaining 12 rats received electroacupuncture intervention at Zhongwan within 5 to 25 minutes after intragastric administration of diluted hydrochloric acid,with a duration of one minute.The GSW area under the curve and extracellular discharge frequency of NTS and DMV neurons were compared between the 1-minute intervals before and after electroacupuncture intervention.Results Compared to the baseline before intragastric administration,the area under the curve of GSW significantly increased at 1,5,10,15,20,and 25 minutes after intragastric administration,and the extracellular discharge frequency of excitatory neurons in the NTS(accounting for 90%,57/63)significantly increased at 1,5,10,15,20,25,30,35,and 40 minutes,both reaching peak values at 1 minute after intragastric administration(P<0.01 or P<0.05).The extracellular discharge frequency of inhibitory neurons in the DMV(accounting for 91%,20/22)showed a non-significant increase at 1 minute after intragastric administration(P>0.05),but significantly decreased at other timepoints(P<0.05).Compared to the baseline before electroacupuncture intervention,the GSW area under the curve and the extracellular discharge frequency of excitatory neurons in the NTS significantly decreased(P<0.05),while the extracellular discharge frequency of inhibitory neurons in the DMV showed no significant difference(P>0.05).Conclusion Electroacupuncture at Zhongwan can improve gastric nociceptive response induced by gastric acid stimulation,possibly by reducing the transmission of visceral sensation and decreasing the excitability of NTS neurons in the medulla.