P2X₇ And P2Y₁ Receptors In The DRG Mediated Analgesia Effect Of Electroacupuncture On Rats With IBS Visceral Pain

Objective:To explore the mechanism of the P2X₇and P2X₃ in DRG in relieving visceral hypersensitivity by electroacupuncture at zusanli?ST36?and sanyin jiao?SP6?.Methods:Pathomorphology,Pain behavior,intrathecal injection,nerve retrograde tracer of intestinal wall,electrophysiology,molecular biology and other methods were used to investigate the neuromolecular mechanism of P2X₇and P2X₃ mediating electroacupuncture at zusanli?ST36?and sanyin jiao?SP6?to relieve visceral pain of IBS-induced by TNBS.Results:Eelectroacupuncture significantly inhibited visceral hypersensitivity which was partially inhibited by intrathecal injection of FCA.Electroacupuncture could inhibit the excitability of DRG neurons in rats with visceral pain:the resting membrane potential was reduced,the rheobase was increased,and the action potentials were inhibited.The regulatory effect of electroacupuncture after intrathecal injection of FCA was inhibited to some extent,suggesting that glial cells may be involved in the regulation of EA on electrophysiological characteristics of neurons.P2X₇ selective agonist Bz ATP increases AWR scores,and antagonist A740003 inhibits AWR scores,indicating that P2X₇ plays a promoting role in visceral pain.Bz ATP antagonized the analgesic effect of electroacupuncture,and A740003 could cooperate with the analgesic effect of electroacupuncture.Electroacupuncture significantly inhibited P2X₇ protein and m RNA level.P2Y₁ agonist ADP-?-s decreased AWR scores,while P2Y₁ antagonist MRS2179had no effect on the score.TNBS down-regulates P2Y₁ protein and its m RNA expression in DRG,suggesting that P2Y₁ plays an inhibitory role in visceral pain.ADP-?-s synergistic analgesic effect of electroacupuncture,and MRS2179 antagonizes the analgesic effect of electroacupuncture,suggesting that P2Y₁ mediates electroacupuncture to relieve visceral hypersensitivity process.MRS2179 inhibits the analgesic effect of A740003.TNBS induces P2Y₁ expression down-regulation,Bz ATP down-regulates P2Y₁ protein and its m RNA expression,and A740003 up-regulates its expression,indicating that P2Y₁ is involved in regulation of P2X₇ on visceral pain.In rats with visceral pain,P2X₃ expression was up-regulated in DRG,Bz ATP expression was further up-regulated,and A740003 expression was inhibited.Bz ATP antagonistic electroacupuncture increased P2Y₁,A740003 synergistic EA increased P2Y₁.Bz ATP antagonized P2X₃ down-regulated by electroacupuncture,and A740003 synergistic electroacupuncture inhibited P2X₃,suggesting that P2X₇-mediated electroacupuncture alleviated visceral pain.TNBS can up-regulate P2X₃ expression,ADP-?-s can down-regulate P2X₃ expression in DRG,and MRS2179 can further up-regulate P2X₃expression.TNBS up-regulated P2X₃ m RNA expression in colon-related DRG;ADP-?-s down-regulated P2X₃ m RNA expression,and MRS2179 further up-regulated P2X₃m RNA expression.This indicates that P2Y₁ modulates visceral pain perception by regulating the expression of P2X₃ receptor protein and its m RNA.Electroacupuncture significantly inhibited the expression of P2X₃ protein.ADP-?-s synergistic electroacupuncture targets the downregulation of P2X₃ protein,while MRS2179antagonizes the downregulation of electroacupuncture.ConclusionGlial cells in DRG participate in the maintenance of peripheral sensitization of IBS visceral pain induced by TNBS and Electroacupuncture analgesic effect.P2X₇ and P2Y₁receptors in DRG mediate visceral hypersensitivity and analgesic effect of electroacupuncture on rats with IBS.