孤束核中GABAB受体在电针“足三里”抑制一过性食管下括约肌松弛中的作用

The Role of GABAB Receptors in Rat Nucleus of Solitary Tract in Inhibiting Frequencies of Transient Lower Esophageal Sphincter Relaxation by Electroacupuncture at "Zusanli"

[目的]探讨电针"足三里"穴对一过性下食管括约肌松弛(transient lower esophageal sphincter relaxation,TLESR)的影响及其机制。[方法]SD雄性大鼠随机分为5组:模型组、足三里组、非经非穴组、γ-氨基丁酸(γ-aminobutiric acid,GABA)B受体阻断剂(沙克洛芬)组和空白注射组。通过逐次向胃内注水的方法建立胃扩张诱发TLESR的动物模型。各治疗组在胃扩张的同时给予电针刺激,持续60min。测压前30分钟,向孤束核区注射GABAB受体阻断剂(沙克洛芬),用低顺应性毛细管灌注测压系统记录、分析TLESR频率及合并反流发生率。免疫组织化学法观察孤束核区GABAB受体表达。[结果]与模型组相比,足三里组可以显著降低TLESR频率及合并反流发生率;与空白注射组相比,GABAB受体阻断剂(沙克洛芬)组的TLESR频率及合并反流发生率上调,提示沙克洛芬可以逆转电针"足三里"穴对TLESR的抑制。与模型组相比,足三里组、空白注射组及沙克洛芬组大鼠孤束核区的GABAB受体表达增加。[结论]电针"足三里"能够减少胃扩张引起的TLESR频率及合并反流发生率,此作用的发挥可能与孤束核内GABAB受体有关。

[Objective] To observe the influence of electroacupuncture of ＂Zusanli＂ on gastric distention induced transient lower esophageal sphincter relaxation（TLESR） in rats. [Methods]Totally 24 SD rats were randomly divided into model group, EA-Zusanli group, EA-non-acupoint group, GABAB receptor antagonist（Saclofen） group and the blank injection group,with 6 rats being in each group.TLESR model was established by extending the stomach with a water balloon.EA was applied to bilateral Zusanli and non-acupoint while gastric distension.GABAB receptor antagonist was given 30 min before EA,The frequency of TLESR and the percentage of common cavity during TLESR were recorded by using a perfused sleeve assembly.The expressions of GABAB receptors were observed by immunohistochemical method. [Results]Compared with the model group, the frequency of TLESR in 1 hour as well as the percentage of common cavity during TLESR was significantly decreased in the EA-Zusanli group.Compared with the blank injection group, the frequency of TLESR and the percentage of common cavity during TLESR were up-regulated significantly in the GABAB receptor antagonist group, suggesting a reduction of the efficacy of EA-Zusanli by GABAB receptor blocked. Compared with the model group, the expression of GABAB receptors in EA-Zusanli group, the blank injection group and GABAB receptor antagonist（Saclofen） group were up-regulated. [Conclusion]EA at Zusanli can reduce both the frequency of TLESR and the percentage of common cavity during TLESR in gastric distension rats, which may be related with GABAB receptor in the solitary nucleus region.