Earpins For Colorectal Expansion Caused By The Impact Of Visceral Pain In Rats

ObjectiveTo investigate the effect of auricular acupuncture on the visceral pain that inducedby colorectal distension in rats.MethodsTwenty-nine female Sprague-Dawley rats were randomly divided into four groupsof control, model, auricular acupuncture (AA) and sham-acupuncture (sham-A). Theelectromyography (EMG) and electrocardiosignal (ECG) were recorded for120minin conscious status. After30min of recording, CRD was performed in group model,AA, sham-A, lasting90min. After recording EMG and ECG, spike of externaloblique muscle of abdomen and heart rate variability (HRV) were analyzed toevaluate the severity of visceral pain and activity of autonomic nervous system. ThemRNA expression of5-HT1Areceptor in colon and raphe nuclei were measured byreal time fluorescent quantitative PCR.ResultsThe baseline of EMG and HRV in four groups has no obvious difference (P>0.05).During pre-stimulation, EMG of model group, AA group and sham-A groupincreased significantly compared with control group (P<0.05), and HRV had noobvious change (P>0.05). After auricular acupuncture, EMG and mRNA expressionof5-HT1Areceptors in colon in AA group decreased significantly compared withmodel group and sham-A group (P<0.05). The mRNA expression of5-HT1Areceptors in raphe nuclei in AA group was lower than that in control group, modelgroup and sham-A group (P<0.05). ConclusionAuricular acupuncture can ameliorate visceral pain induced by CRD in rats,probably via5-ht system.