Electroacupuncture Shangjuxu The Regulatory Role Of The Acute Restraint Stress In Rat Colon Function And Central Mechanisms

Objective:The aim of this study was to prove the regulation effect of acupuncture ST 37 on acute restraint stress -induced colonal disfunction in rat and explore its centeral mechanism.To get the experimental evidence of the relationship between Shangjuxu point(ST 37)and large intestine Fu-organ and academic guidance on clinical practice against stress-related functional bowel disorders(such as irritable bowel syndrome),ST 37 were used as representative point of the lower sea points guided by the theory of "curing Fu-organ diseases by sea points" and Quchi point(LI 4,sea point of large intestine meridian)as the control point.Methods:40 male Sprague-Dawley rats were divided into 4 grops:control group,model group,ST37 group and LI 4 group.Restraint stress for 1.5h were performed in all groups except the control group.After one hour's stress,electro-acupuncture on ST37 and LI4 were administered respectively in ST37 group and LI4 group.The changes of the pain threshold pressure of colon and the time of bead excretion in every group were observed after stress,the expression of c-fos in spinal segments L6-S1 and the expression of c-fos/CRH in locus coeruleus(LC)were examined by immunocytochemical method. The expression of CRH1RmRNA in LC were detected with in situ hybridization technique.The electrophysiological experiments were performed on 40 healthy mature male Sprague-Dawley rats,anesthetized with an intraperitoneal injection of urethane.Discharges from individual single neurons in LC were recorded extracellularly with the use of glass microelectrodes.The effects of manual acupuncture at ST37 and LI 4 on the response of LC neurons to noxious colonal distension were observed.Results:Model group showed decrease in the pressure of pain threshold and the time of bead excretion in distal colon(p＜0.01).Compared with model group,the time of bead excretion in ST 37 group was longer(p＜0.05)and the pressure of pain threshold was elevated(p＜0.01).There was no significant difference of that between LI 4 group and model group(p＞0.05).Significant difference of that showed between LI 4 group and ST 37 group(p＜0.05).Following stress,c-fos protein express in both spinal segments L6-S1 and LC,which were both significantly higher than control rats(P＜0.05).After EA ST 37 point(p＜0.05)but no LI 4(p＞0.05),c-fos expression decreased significantly compared with model group.There was significant difference of that between LI 4 group and ST37 group(p＜0.05).CRH and CRH-1RmRNA expressed in LC were increased in model group compared with control group(p＜0.05).EA ST 37(p＜0.05)but no IL 4(p＞0.05)decreased the expression of CRH and CRH1R mRNA in LC following restraint stress compared with model group.There was significant difference of that between LI 4 group and model group(p＜0.05).Colonal distention noxious afferent could significantly activate LC neurons(p＜0.01).Acupuncture at either ST 37(p＜0.01)or LI 4(p＜0.01)inhibit this noxious response.And there was significant difference between the two points.(p＜0.01),the inhibitory effect of ST37 was stronger than that of LI 4.Conclusion:1 EA of ST 37 but no LI 4 had significant effect on restraint stress-induced(centreral) colonal disfunction including increased colon motility and visceral hypersensitivity,it indicates a particular relation between ST 37 and large intestine fu-organ and it may have benefit against stress -related functional bowel disorders.The theory of "curing fu-organ diseases by sea points" has its scientific contents.2 The somato-visceral convergent neurons in LC may play an important role in the neural basis of the relationship between ST 37 and large intestine Fu-organ.3 The results mentioned above indicated that spinal segments L6-S1 and LC were important nerve centers of the relationship between ST 37 and large intestine Fu-organ when facing stess.Reducing the activation of neurons in spinal segments and LC, suppressing the expression of CRH and CRH-R1mRNA in LC were possible central mechanism of acupuncture ST 37 against restraint stress-induced colonic disfunction.