Mechanism of dorsal root ganglion SERT in electroacupuncture regulation of P2X3 receptor-mediated visceral hypersensitivity in IBS rats

Objective:To investigate the role of serotonin reuptake transporter(SERT)and P2X3 receptor of dorsal root ganglion(DRG)in regulating visceral hypersensitivity of rats with irritable bowel syndrome(IBS)by electroacupuncture(EA).Methods:Male Sprague-Dawley and SERT^(-/-)rats were subjected to preparing IBS visceral hypersensitivity models with 2,4,6-trinitrobenzene sulfonic acid(TNBS)enema.Three weeks post-modeling,interventions including EA,intrathecal injection,and EA plus intrathecal injection were applied,respectively.Hematoxylin-eosin staining and abdominal withdrawal reflex(AWR)score were used to confirm the successful establishment of the IBS model.AWR score,whole-cell patch clamp technique,and Western blotting assay were used to evaluate the changes in visceral pain sensitivity,electrophysiological properties of DRG neurons,and the expression of DRG P2X3 receptor and SERT in IBS rats.Results:Compared to the model group,the AWR score in the EA group decreased significantly(P<0.05),the resting membrane potential(P<0.05)and the number of action potentials(P<0.05)of DRG neurons reduced,and the baseline intensity increased(P<0.05);additionally,the expression of P2X3 receptor in DRG decreased(P<0.01),and the SERT expression increased(P<0.05).Compared to the P2X3 receptor agonist group,the SERT protein expression in DRG was higher in the EA group.In SERT^(-/-)rats,the P2X3 receptor expression in DRG increased in the EA group compared to the model group(P<0.01).Conclusion:EA modulates the electrophysiological characteristics of intestinal primary sensory neurons by regulating the expression of SERT and P2X3 receptor in DRG of IBS rats.This modulation may contribute to the mechanism by which EA alleviates peripheral sensitization of visceral pain in IBS rats.

Regulatory effect of mild moxibustion on P2X3 receptors in spinal cord,anterior cingulate cortex and thalamic ventral posterolateral nucleus of rats with IBS visceral hyperalgesia

Objective To observe the therapeutic effect of mild moxibustion on irritable bowel syndrome(IBS)visceral hyperalgesia model rats and its regulatory effect on P2X3 receptors in the spinal cord,anterior cingutate cortex(ACC)and thalamic ventral posterolateral nucleus(VPL).Methods Thirty 8-day-old newborn rats were randomly divided into a normal group(n=6)and a modeling group(n=24)according to the completely random number table method.Rats in the normal group were bred routinely,and those in the modeling group were subjected to preparing IBS chronic visceral hyperalgesia model using colorectal distention(CRD)in stimulation method.Rats successfully modelled were re-divided into a model group,a mild moxibustion group,a P2X3 receptor antagonist group,and a normal saline group according to the completely random number table method with 6 rats in each group.Rats in each group received corresponding interventions from the 37-day old,once a day for 7 consecutive days.Immunohistochemistry and Western blot assays were used to detect P2X3 protein expressions in the spinal cord,ACC and VPL of rats.Results Under different intensities of CRD stimulation,the abdominal withdrawal reflex(AWR)scores of the model group were significantly increased versus the normal group(all P<0.05);the AWR scores of the mild moxibustion group and the P2X3 receptor antagonist group were significantly reduced versus the model group(all P<0.01).The P2X3 protein expressions in rat spinal cord,ACC and VPL tissues of the model group were significantly increased versus the normal group(all P<0.01);the P2X3 protein expressions in rat spinal cord,ACC and VPL tissues of the mild moxibustion group and the P2X3 receptor antagonist group were significantly reduced versus the model group(all P<0.01).Conclusion Mild moxibustion can inhibit the P2X3 receptor expressions in the spinal cord,ACC,and VPL tissues of IBS visceral hyperalgesia model rats,which may be the mechanism of mild moxibustion in relieving the central sensitization of rats with IBS visceral hyperalgesia.

Adenosine triphosphate mediates the pain tolerance effect of manual acupuncture at Zusanli(ST36) in mice

OBJECTIVE:To investigate the mechanisms behind the effects of acupuncture in Traditional Chinese Medicine,we delved into the adenosine triphosphate/peripheral purinergic P2X receptor 3(ATP/P2X3)receptor signaling system as an indicator of the body's energy state,commonly referred to as"Qi".METHODS:The tail-flick test was utilized to explore the impact of acupuncture on pain tolerance threshold(PTT)in mice,while also assessing adenosine(ADO)levels and adenylate energy charge(EC)at Zusanli(ST36).The study further investigated the dose-dependent effects of acupuncture on PTT and ADO levels at Zusanli(ST36).To shed light on the underlying mechanisms of acupuncture's effects,the study examined the impact of ATP,a P2X3 receptor antagonist,and adenosine disodium on PTT following acupuncture administration.RESULTS:Acupuncture at Zusanli(ST36)led to significant improvements in PTT in mice,with the most effective interventions being twirling for 2 min and needle retention for 28 min.These interventions also resulted in significant increases in ATP levels.The effects of acupuncture were further augmented by administration of different doses of ATP at Zusanli(ST36),and pretreatment with a P2X3 receptor antagonist decreased PTT.Adenylate EC peaked at 30 min after intraperitoneal injection of ATP,and pretreatment with various doses of i.p.ATP 30 min prior to acupuncture increased PTT in a dose-dependent manner.Additionally,pretreatment with an i.p.or intramuscular injection of adenosine disodium enhanced the effects of acupuncture.CONCLUSION:This research provides compelling evidence that ATP is involved in the regulation of PTT through acupuncture,revealing new avenues for achieving enhanced clinical outcomes.