针刺“足三里”对下丘脑外侧区-小脑顶核环路胃扩张敏感性神经元的作用研究

Effects of acupuncture at “Zusanli” (ST36) on sensitive neurons of gastric distention in LHA-FN circuit in rats

目的：观察针刺＂足三里＂对下丘脑外侧区-小脑顶核（LHA-FN）环路胃扩张（gastric distention,GD）敏感性神经元的调节作用,探索针刺足三里调节胃功能的中枢机制。方法：将101只大鼠随机分为下丘脑外侧区（lateral hypothalamus area,LHA）组和小脑顶核（fastigial nuclear,FN）组,LHA组50只、FN组51只。所有大鼠行胃扩张手术。根据大鼠脑立体定位图定位LHA和FN坐标后开颅,剥离硬脑膜暴露脑组织,并用温石蜡油覆盖防止干燥,采用玻璃微电极探查神经元放电,进行细胞外记录,LHA组观察下丘脑外侧区GD敏感性神经元电活动,FN组观察小脑顶核GD敏感性神经元电活动。记录到神经元电信号后1min开始针刺干预,直刺左侧＂足三里＂5mm,平补平泻,120～180次/min,刺激1 min。观察针刺对侧＂足三里＂对LHA和FN的GD敏感性神经元自发放电的影响。结果：（1）LHA组共记录到自发放电的LHA神经元54个,FN组共记录到自发放电的FN神经元85个。其中LHA组以GD兴奋性神经元为主（46.3%）,FN组以GD无反应性神经元为主（54.12%）;FN组的GD无反应性神经元平均放电频率为（39.03±14.91）spikes/s,GD兴奋性神经元平均放电频率为（19.67±12.08）spikes/s,GD抑制性神经元平均放电频率为（28.76±7.26）spikes/s,与胃扩张前比较差异均有统计学意义（均P〈0.01）。（2）针刺对LHA组GD兴奋性神经元表现出兴奋效应,对GD抑制性神经元表现出抑制效应（P〈0.05）;FN组,针刺主要作用于GD抑制性神经元,且以兴奋作用为主,针刺对GD兴奋性神经元无效（P〈0.01）。结论：胃扩张信号和针刺信号能在LHA和FN汇聚,针刺对不同核团同类型GD敏感性神经元具有不同的调节作用,LHA-FN环路可能参与针刺调节胃功能的中枢整合机制。

Objective To observe the regulation effects of acupuncture at＂Zusanli＂（ST 36）on sensitive neurons of gastric distention（GD）in lateral hypothalamus area（LHA）and fastigial nuclear（FN）circuit,and to explore the central mechanism of acupuncture for gastric function.Methods A total of 101 rats were randomly assigned into a LHA group（50rats）and a FN group（51rats）.Gastric distension surgery was performed in all the rats.According to the stereotaxic atlas of rat brain,the LHA and FN were located,followed by craniotomy.The endocranium was removed to exposure brain tissue,and warm paraffin oil was used to prevent desiccation.The electrical activities of neurons were probed by glass microelectrode to perform extracellular recording.The electrical activities of GD sensitive neurons in LHA were observed in LHA group,while those in FN were observed in FN group.One min after the electrical signal of neurons was recorded,acupuncture was given at left＂Zusanli＂（ST 36）with mild reinforcing and attenuating technique,120～180times/min for 1 min.The effects of acupuncture at ＂Zusanli＂（ST 36）on spontaneous discharge of GD sensitive neurons in LHA and FN were observed.Results（1）Totally54LHA neurons of spontaneous discharge in LHA group and 85 FN neurons in FN group were recorded.GDexcitatory（GD-E）neurons were mainly in the LHA group（46.3%）and GD-non-response（GD-N）neurons were mainly in the FN group（54.12%）.The average discharge frequency of GD-N neurons was（39.03±14.91）spikes/s,that of GD-E neurons was（19.67±12.08）spikes/s,and that of GD-inhibitory（GD-I）neurons was（28.76±7.26）spikes/s,which were statistically different from those before GD（all P〈0.01）.（2）In LHA group,acupuncture excited the activity of GD-E neurons,and inhibited the activity of GD-I neurons（P〈0.05）;in FN group,acupuncture excited the activity of GD-I neurons,but showed no effect on GD-E neurons（P〈0.01）.Conclusion The signal of GD and acupuncture could converge in LHA and FN;acupuncture presented different regulation effects on identical type of GD-sensitive neurons in different nuclear groups;LHA-FN circuit might participate in central integration mechanism of acupuncture on gastric function.