三叉神经痛大鼠延髓内GABA_B受体的变化

Change of GABA_B Receptor in Medulla of Trigeminal Neuralgia on Rats

目的 通过建立大鼠三叉神经痛模型，探讨GABAB受体与三叉神经痛发病机制的关系。方法 12只SD大鼠随机分为4组（n=3）。A、C组为手术组，B、D组为假手术组。手术组用铬线疏松结扎大鼠右侧眶下神经造成慢性缩窄性损伤，而假手术组只暴露神经，不结扎。观察术前和术后3、6、9、12、15d大鼠对机械性疼痛刺激的反应阈值。A、B组术后第9天，C、D组术后第15天分别取大鼠延髓组织，实时定量PCR法测大鼠延髓内GABA。受体的量。结果 术后9～15d，手术组较假手术组大鼠右眶下神经支配区域机械性痛觉超敏（P〈0．05）。A组延髓内GABAB1和GABAB2受体量较B组多（P〈0．05），C组延髓内GABAB1和GABAB2受体量较D组多（P〈0．05）。结论 眶下神经的慢性环扎损伤可导致大鼠三叉神经痛，且大鼠疼痛时GABAB受体的表达增高。

Objective To assess the relationship between GABAB receptor in medulla and trigeminal neuralgia on rats. Methods Twelve SD rats were randomly divided into 4 groups, 3 for each group. Group A and B were surgical groups, while Group C and D were sham surgical ones. In the surgical group, right unilateral chronical constriction injury（CCI） of rats was produced by placing loose chromic gut ligature around the infraorbital nerve （ION）. In the sham surgical group, the ION was only exposed using the same procedure but not ligated. Mechanical response threshold was observed before operation and 3, 6, 9, 12 and 15 clays after operation. Medullas of rats in group A and B were taken to measure the quantity of GABAB receptor by real-time PCR 9 clays after operation, and medullas of rats in group C and D were clone 15 clays after operation. Results Compared with the sham surgical group, an allodynia to mechanical stimulation on the territory of ligated ION was found from the ninth to fifteenth day after operation in surgical group（P 〈0.05）. The quantity of GABAB1 and GABAB2 receptor in medulla in group A was higher than that in group B（P 〈0.05） , and the quantity of GABAB1 and GABAB2 receptor in medulla in group C was also higher than that in group D（P 〈0.05）. Conclusion CCI-ION can result in trigeminal neuralgia on rat and there is an increase of quantity of GABAB receptor in neuralgia.