三叉神经损伤大鼠延髓内γ-氨基丁酸A受体的变化

目的：以实时定量聚合酶链反应（PCR）测定三叉神经损伤大鼠延髓内γ-氨基丁酸A（GABAA）受体量的变化，探讨GABAA受体与三叉神经痛发病机制的关系。方法：20只SD大鼠随机分为4组，每组各5只。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时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法测定大鼠延髓内GABA。受体α1、α2、α3的3个亚基的量。采用SAS6．12软件包进行两样本均数的t检验。结果：术后第9—15天，结扎组大鼠较假手术组，右眶下神经支配区域机械性痛觉超敏（P〈0．05）。A组延髓内GABAAα1、GABAAα2、GABAAα3受体量与B组无显著差异，C组延髓内GABAAαl、GABAAα2、GABAAα3受体量与D组无显著差异。结论：眶下神经的慢性环扎损伤可导致大鼠三叉神经痛，大鼠疼痛时GABAA受体α1、α2、α3的3个亚基并不参与其中。

Changes of GABAA receptor in medulla of injury of trigeminal nerve in rats

PURPOSE: To assess the relationship between GABAA receptor in rats's medulla and injury of rats's trigeminal nerve by using real-time polymerase chain reaction(PCR). METHODS: Twenty SD rats were divided into four groups randomly, five rats in each group. Group A and group C were surgical groups, Group B and group D were sham surgical groups. In the surgical group, right unilateral chronical constriction injury(CCI) of rat 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, 15 days after operation. Medullas of rats in group A and B were taken to measure the quantity of GABA(Aalpha1),GABA(Aalpha2),GABA(Aalpha3) receptor by real-time PCR 9 days after operation, and medullas of rats in group C and D were done 15 days after operation. The data were analysed by Students's t test by SAS6.12 software package. RESULTS: Compared with the sham surgical group, an allodynia to mechanical stimulation on the territory of ligated ION was found from the 9th to 15th day after operation in the surgical group(P<0.05).There was no difference in GABA(Aalpha1) receptor, GABA(Aalpha2) receptor, GABA(Aalpha3) receptor between group A and group C, also there was no difference in GABA(Aalpha1) receptor, GABA(Aalpha2) receptor, GABA(Aalpha3) receptor between group B and group D. CONCLUSIONS: CCI-ION can result in trigeminal neuralgia on rat. Trigeminal neuralgia of rat may not be associated with GABA(Aalpha1) receptor, GABA(Aalpha2) receptor and GABA(Aalpha3) receptor.