The Neurobiology Mechanism By Which The Dorsal Vagal Complex And Gastrointestinal Hormone Receptors Mediates The Regulation Of Gastric Motility By Back-shu And Front-Mu Points Stimulation

Background:The combination of Back-shu and Front-mu acupoints is one of the commonlyused effective methods in clinical acupuncture practice, Back-shu and Front-muacupoints could cure diseases of Zang-fu viscera. Numerous studies have conducted toexplore the mechanism of electro-acupuncture (EA) at gastric Shu-and-Mu points andfind out that it could significantly enhance gastric motility, with combined stimulationof these acupoints eliciting a synergistic effect. Previous evidences have shown that EAsignals of Shu acupoints and Mu acupoints gathered in the spinal cord. As a result, Itoffers important theoretical and practical significant to clarify whether the advancedcentral nervous system, such as medulla, hypothalamus, hippocampus are involved inthe regulation of the gastric motility by Zhongwan(RN12, a front-Mu acupoint ofstomach) and Weishu(BL21, a back-Shu acupoint of stomach) stimulation.Objective：To observe the regulate effect of gastric motility by EA at RN12and BL21ingastric distention model rats、the neuron-activating effects of EA in Dorsal VagalComplex (DVC)、the expression of Motilin Receptor（MTL-R）and Gastrin Receptor(GAS-R) in both the hypothalamus and gastric antrum. Our research endeavored toverify the central target and neural channel mediating the regulation of gastric motilityby EA at RN12and BL21, in order to reveal the neurobiological mechanisms of EA atBack-shu and Front-mu acupoints, and raise theory basis for clinical application.Methods:Healthy adult SD rats were randomly divided into several groups. The gastricdistention model is made by inserting a rub balloon into rats’ stomach and filling it with water, which is used to record waveform of gastric motility. Bilateral DVC wasdestroyed by a lesion-making device and acute bilateral sub-diaphragmatic vagotomywas performed, they were created to explore the role of DVC and vagus in gastricmotility. The neuron-activating effects of EA on these group in DVC were studiedusing the discharge of neuron as an index. The expression level of MTL-R and GAS-Rin both the hypothalamus and gastric antrum were assayed by Western blot(WB).Results：1. Changes of the gastric movement:(1) Compared with those in the pre-EAgroup, the amplitudes of gastric movement increased significantly in all these groups(p<0.01); and they were statistically increased in RN12+BL21group and RN12groupcompared with those in RN12group (p<0.01or p<0.05); EA had no significant effectson the frequency of gastric movement(p>0.05).(2) Compared with those in the MODgroup, the amplitudes of gastric movement decreased significantly in the DVC lesiongroup and DVC lesion+EA group (p<0.05); it also decreased significantly in vagotomygroup and vagotomy+EA group (p<0.05); compared with those in the sham lesion group,the amplitudes of gastric movement decreased significantly in the DVC lesion groupand DVC lesion+EA group (p<0.05); it also decreased significantly in vagotomy groupand vagotomy+EA group (p<0.05); compared with those in the sham operation group,the amplitudes of gastric movement decreased significantly in the vagotomy group andvagotomy+EAgroup (p<0.05).2. Neuron-activating effects of gastric distension sensitive neurons in DVC:(1)Compared with MOD group, the neuron-activating frequency of gastric distensionsensitive neurons increased significantly in RN12+BL21group、RN12group and BL21group (p<0.01); EA had no significant effects in non-acupoint group(p>0.05).(2)Compared with RN12+BL21group, the neuron-activating frequency in RN12groupand BL21group are relatively low(p<0.01).3. The expression of MTL-R and GAS-R in hypothalamus:(1) Compared with MOD group, the expression of MTL-R and GAS-R in hypothalamus increasedsignificantly in RN12+BL21group、RN12group and BL21group (p<0.01); MTL-Rhad no significant expression in non-acupoint group(p>0.05).(2) Compared withRN12+BL21group, the expression of MTL-R and GAS-R of hypothalamus in RN12group and BL21group are relatively low(p<0.01).4. The expression of MTL-R and GAS-R in gastric antrum:(1) Compared withMOD group, the expression of MTL-R and GAS-R in gastric antrum increasedsignificantly in RN12+BL21group、RN12group and BL21group (p<0.01); GAS-Rhad no significant expression in non-acupoint group(p>0.05).(2) Compared withRN12+BL21group, the expression of MTL-R and GAS-R of gastric antrum in RN12group and BL21group are relatively low(p<0.01).Conclusion:1. EA stimulation of the gastric Shu and Mu points can significantly enhancegastric motility, and acupuncture signal gathers in DVC and vagus plays an importantrole in the regulation of gastric motility.2. EA stimulation of the gastric Shu and Mu points may result in elevatinggastrointestinal hormones in hypothalamus and gastric antrum, humor may be partiallyinvolved in the mechanism of EA.3. The effect of combined EA stimulation of gastric Shu and Mu points may beachieved through the hypothalamus-DVC-vagus-gastric neural pathway.