Role of GABAA receptors in uninjured dorsal root ganglion in a rat model of neuropathic pain

Objective To evaluate the role of GABAA receptors in uninjured dorsal root ganglion(L4DRG)in a rat model of neuropathic pain.Methods Thirty adult female SD rats weighing 200-250 g were randomly divided into 3 groups(n = 10 each): control group(group C),muscimol group(group M)and bicuculline group(group B).Neuropathic pain was produced by L5 spinal nerve ligation.Normal saline 50 μl,GABAA receptor agonist-muscimol 50 μl or GABAA receptor antagonist- bicucullin 50 μl was injected into the L4 DRG.The thermal pain threshold and mechanical pain threshold were measured and recorded from 1 day before operation to 10 days after operation.Results Compared with group C,the mechanical pain threshold was significantly increased(P ＜ 0.05),while no significant difference was found in thermal pain threshold in group M(P ＞ 0.05),and the thermal pain threshold and mechanical pain threshold were significantly decreased in group B(P ＜ 0.05).Conclusion Activation of GABAA receptors in uninjured DRG is involved in mechanical hyperalgesia in a rat model of neuropathic pain,but it dose not play a leading role. Key words: Neuralgia; Receptors,GABA-A; Ganglia,spinal