GAD67-GFP基因敲入小鼠三叉上核内向三叉神经运动核投射的GFP阳性神经元表达c-fos的研究

本文综合应用逆行束路追踪(将四甲基罗达明-TMR注入一侧三叉神经运动核)和免疫荧光组织化学三重标记技术,在激光共聚焦显微镜下对谷氨酸脱羧酶67-绿色荧光蛋白(GAD67-GFP)基因敲入小鼠在口周部给予伤害性刺激时,三叉上核(Vsup)内向对侧三叉神经运动核(Vmo)投射的呈GFP阳性的GABA能神经元表达c-fos的情况进行了研究。结果显示:(1)Vsup内可观察到许多GFP阳性神经元,细胞较小;(2)也可观察到许多TMR或c-fos单标神经元较密集地分布于Vsup内,其中c-fos阳性产物只见于神经元的胞核,在胞浆内未见表达;(3)在激光共聚焦显微镜下可进一步观察到部分神经元同时呈GFP/TMR、TMR/c-fos、GFP/c-fos双重标记或GFP/TMR/c-fos三重标记。其中GFP/TMR双标神经元分别占GFP或TMR阳性神经元的17.8%和19.2%;TMR/c-fos双标神经元分别占TMR或c-fos阳性神经元的34.9%和31.3%;GFP/c-fos双标神经元分别占GFP或c-fos阳性神经元的21.2%和20.5%;而GFP/TMR/c-fos三标神经元分别占GFP、TMR或c-fos阳性神经元的11.1%、12%和10.8%。以上结果表明小鼠Vsup内部分GABA能神经元可接受来自同侧的口面部伤害性信息,并对这些信息进行整合后,直接发出投射纤维至Vmo;故Vsup内部分GABA能运动前神经元可能参与口面部伤害性反射局部环路的构成。

c-fos EXPRESSION IN GFP-POSITIVE NEURONS OF THE SUPRATRIGEMINAL NUCLEUS PROJECTED TO TRIGEMINAL MOTOR NUCLEUS IN GAD67-GFP KNOCK-IN MOUSE

The present study used retrograde tract-tracing [tetramethylrhodamine(TMR) injected unilaterally into the trigeminal motor nucleus(Vmo)] combining with triple-immunofluorescence histochemical technique to observe c-fos-expression in the GABAergic neurons which labeled green fluorescence protein(GFP) and projected into the contralateral trigeminal motoneurons in the supratrigeminal nucleus(Vsup) of glutamate decarboxylase67-GFP(GAD67-GFP) knock-in mouse following noxious stimulation of the orofacial region under a confocal laser-scanning microscope.The results showed that:(1)Many of GFP-positive neurons were observed in the Vsup and the vast majority of them were small neurons;(2)Some of single TMR-labeled or c-fos-immunopositive neurons were densely distributed in the Vsup,and c-fos-immunoreactivities only expressed in the neuronal karyoplasm,not in cytoplasm;(3)Some of neurons in the Vsup were found to be double-labeled for GFP/TMR,TMR/c-fos or GFP/c-fos and triple-labeled for GFP/TMR/c-fos under confocal laser-scanning microscope.The proportion of GFP/TMR double-labeled neurons was about 17.8% and 19.2% of total population of GFP-and TMR-positive neurons,respectively.TMR/c-fos double-labeled neurons constituted 34.9% and 31.3% of the total population of TMR-or c-fos-positive neurons.About 21.2%,20.5% of GFP-and c-fos-positive neurons were GFP/c-fos-immunopositive,respectively.On the other hand,the proportion of GFP/TMR/c-fos triple-labeled neurons was about 11.1%,12% and 10.8% of total population of GFP-,TMR-and c-fos-positive neurons,respectively.The above results indicated that some GABAergic neurons in the Vsup can receive the ipilateral orofacial nociceptive informations,and then integrate and transform them directly into the Vmo.Therefore,some GABAergic neurons in the Vsup may be involved in the circuits of orofacial nociceptive reflexes.