Study On The Effect Of Electroacupuncture At "Yintang" And "Dachangshu" Points On The Discharge Of VPL And ACC Neurons In IBS-D Model Rats

OjectiveIn this experiment,we started from both ends of the brain-gut axis to observe the effects of electroacupuncture(EA)at "Yintang(EX-HN3),and "Dachangshu(BL 25)" on the intestinal tract and mood of IBS-D model rats.Combining their effects on the expression of dopamine D2 receptor(D2R)and the neuron firing of nucleus ventralis posteriolateralis(VPL)and anterior cingulate cortex(ACC)neurons,we explore the differences in effects and related mechanisms of acupoints with different indications,to promote the mechanism recognition of the effect specificity of meridians and acupoints.Methods64 Wistar newborn rats were Randomly divided into 4 groups:blank group,model group for contrast,EX-HN3 group and BL 25 group for Intervention.Use joint methods for modeling.Rats at 9 weeks old were given EA at corresponding acupoints once every other day for 5 times.Record the Bristol stool score before and after EA;4 index of abdominal withdrawal reflex(AWR)to assess the intestinal sensitivity and motility;2 index of open field test(OFT)to evaluate the emotional state;the expression of dopamine D2 receptor(D2R)in dorsal motor nucleus of vagus(DMV)and colon detected by immunohistochemistry;the neuron firing of VPL and ACC recorded by multichannel in vivo synchronous recording technology to observe and analyze their firing characteristics.Results1 Effect of EA on Bristol stool score in IBS ratsBefore acupuncture:compared with the blank group,the Bristol stool score of the rest 3 groups increased significantly(P<0.01),which indicates that the molding is successfulAfter acupuncture:Compared with the blank group,the score in model group increased significantly(P<0.01).Compared with the model group,the scores of EX-HN3 group and BL 25 group were reduced(P<0.05,P<0.01);the score of BL 25 group decreased after EA(P<0.05).2 Effect of EA on AWR in IBS ratsCompared with the blank group,the latent period and the pressure of the first contrast wave decreased significantly(P<0.01),the number of the contraction waves and the peak-peak value increased significantly(P<0.01)in model group.Compared with the model group,the latent period and the pressure of the first contrast wave significantly increased(P<0.01),and the number of contract waves&peak-peak value decreased significantly(P<0.01)in BL 25 group.Compared with the EX-HN3 group,the latent period significantly increased(P<0.01),the number of contract waves&peak-peak value significantly decreased(P<0.05)in BL 25 group.3 Effect of EA on OFT in IBS ratsCompared with the blank group,the horizontal and vertical mo vements of model group decreased(P<0.05).Compared with the model group,the horizontal and vertical movements of EX-HN3 group increased(P<0.05).The horizontal and vertical movements of BL 25 group plays no significant difference with two contrast groups.4 Effect of EA on the expression of D2R in IBS rats1)In DMV:Compared with the blank group,the expression of D2R in model group was significantly reduced(P<0.01).Compared with the model group,the expression of D2R in two contrast groups increased significantly(P<0.01).2)In colon:Compared with the blank group,the expression of D2R in model group and EX-HN3 group were significantly reduced(P<0.01).Compared with the model group,the expression of D2R in EX-HN3 group and BL 25 group increased(P<0.05,P<0.01).5 Effect of EA on the neuron firing of VPL and ACC in IBS rats1)Effect of EA on the neuron firing of VPL in IBS rats:Compared with the blank group,the neuron firing rate of VPL unit I in model group increased significantly(P<0.01).Compared with the model group,the neuron firing rate of VPL unit I in BL 25 group decreased significantly(P<0.01).Compared with the blank group,the neuron firing rate of VPL unit ? in model group decreased(P<0.05).Compared with the model group,the neuron firing rate of VPL unit ?in EX-HN3 group increased(P<0.05).2)Effect of EA on the neuron firing of ACC in IBS rats:Compared with the blank group,the neuron firing rate of ACC unit ? in model group and BL 25 group decreased significantly(P<0.01).Compared with the model group,the neuron firing rate of ACC unit ? in EX-HN3 group increased(P<0.05).Compared with the blank group,the neuron firing rate of ACC unit ? in model group,EX-HN3 group and BL 25 group decreased(P<0.01,P<0.05,P<0.05).Conclusion1 EA at "EX-HN3" and "BL 25" both can improve the intestinal sensitivity and motility,and relieve IBS symptoms in IBS rats."BL 25" is superior to EX-HN3 in improving intestinal motility and sensitivity and therefore reducing abdominal symptoms." Yintang" can improve the depression of IBS rats.The characteristics of the their effects are consistent with their traditional indications.2 The mechanism of EA at "EX-HN3" and "BL 25" on the improvement of intestinal motility in IBS rats may be related to the regulation of the D2 receptor content at both ends of the brain-gut axis.There are differences in the regulation of these two acupoints.3 EA at "EX-HN3" and "BL 25" have different effects on VPL and ACC neuron firing rate.This difference in effect reflects the specificity of the meridian acupoint effect.Also partly explained the mechanism of acupoints.