Baclofen’s Regulation Function To GABA_A Receptor On DRG Neurons In SD Rat

Objective: To investigate the function and expression GABAAreceptor γ2subunit andα2subunit in CCI (Chronic Constriction Injury) model, and the change of GABAAreceptor γ2subunit and α2subunit in DRG (Dorsal Root ganglion) neurons of CCImodel rat before and after baclofen intervention.Methods:(1) Preparation CCI model of rat,some of them are intervened by gavagemanner;(2) Hot-plate experiment was used to detecting the change of thermalwithdrawal latency (TWL) before and after baclofen intervention in CCI model;(3)whole-cell patch clamp recording technique was used to clarify the change ofGABA-mediated inward currents on DRG neurons before and after baclofenintervention in CCI model;(4)Western blot technique were used to study theexpression of GABAAreceptor γ2subunit before and after baclofen intervention inCCI model;(5)Immunofluorescence technique were used to study the expression ofGABAAreceptor α2subunit in DRG neurons of CCI model.Results:(1) TWL were decreased apparently in CCI model rat compared with normalgroup, the threshold of pain rised after baclofen intervention(p <0.05, n=10);(2)whole-cell patch clamp recording technique showed that GABA-mediated inwardcurrents were reduced obviously in ipsilateral side, but increasing in contralateral sidein CCI model,and baclofen inhibited GABA-mediated inward currents(p<0.05, n=6);(3) Western blot technique showed the expression of GABAAreceptor γ2subunitdown-regulation in both ipsilateral side and contralateral side in CCI modol comparedwith control, but the phosphorylated γ2subunit up-regulation (p <0.05, n=6);(4)Western blot technique showed GABAAreceptor γ2subunit down-regulation in bothipsilateral and contralateral side in CCI model after baclofen intervention, and thephosphorylated γ2subunit was up-regulation;(5) Immunofluorescence techniqueshowed that α2subunit was down-regulated in ipsilateral side, but up-regulated in thecontralateral side of CCI model (p <0.05, n=6).Conclusions: Under the neuropathic pain condition, GABAAreceptor mediated theprocess of the pain. Baclofen, a GABABreceptor agonist, inhibited GABAAreceptorfunction by phosphorylation of GABAAreceptor γ2subunit.