GAD67-GFP基因敲入小鼠5-羟色胺样和P物质样阳性终末与三叉神经中脑核神经元的联系

Association of 5-HT-like and substance P-like immunoreactive terminals with mesencephalic trigeminal nucleus neurons in the GAD67-GFP knock-in mouse

本研究应用免疫荧光组织化学三重标记技术,在激光共聚焦显微镜下观察了GAD67-GFP基因敲入小鼠三叉神经中脑核(Vme)内5-HT样和P物质(substanceP,SP)样阳性终末分别与小白蛋白(parvalbumin,PV)样和GFP阳性神经元之间的联系。结果显示:(1)Vme内有较多的PV样阳性神经元,这些神经元绝大多数为大、中型的假单极神经元,直径约为18～40μm;也可观察到少量的GFP阳性神经元,多为小的多极神经元,直径约为8～15μm;(2)5-HT样阳性终末广泛分布于Vme内,其中有部分阳性终末分别聚集在PV样或GFP阳性的Vme神经元的胞体周围,计数结果表明:大约有77.7%和22.3%的5-HT样阳性终末分别与PV样或GFP阳性胞体相接触;(3)SP样阳性终末也广泛分布于Vme内,并分别与PV样或GFP阳性神经元的胞体形成密切接触,其中有78.2%和21.8%的阳性终末分别与PV样或GFP阳性胞体相接触。以上结果提示,在口面部本体感觉信息向更高一级中枢传递过程中,5-HT能和SP能神经终末不仅对初级传入发挥直接的调控作用,还可能通过影响Vme内的GABA能神经元的活动,从而间接对该信息的传递发挥调控作用。

In the present study, triple-immunofluorescence histochemieal staining technique was used to examine the relationships between 5-HT-like or substance P （SP） -like immunoreactive （-LI） terminals and parvalbumin （PV） -like or GFP-positive neurons in the mesence- phalie trigeminal nucleus （Vine） in the GAD67-GFP knock-in mouse under the eonfocal laser scanning microscope. The results showed： （1） Many Vine neuronal cell bodies showed PV-LI and the majority of them were large or medium pseudounipolar neurons （ diameter： 18-40 μm） ; some GFP-positive neurons were observed in the Vine and these neurons were small multipolar neurons （diameter： 8-15 μm） ; （2） 5-HT-LI terminals were generally distributed in the Vine and some of them surrounded the cell bodies of Vine neurons showing PV-LI or GFP-pesitive, respectively. The quantitative estimation indicated that approximately 77.7% and 22.3% 5-HT-LI terminals made close contact with the PV-LI and GFP-positive Vine neurons, respectively; （3） SP-LI terminals were also distributed in the Vine and some of them made close contact with the PV-LI and GFP-positive Vine neurons. These terminals were 78.2% and 21.8%, respectively. The present results suggest that in the transmission of the proprioceptive sensory information from the orofacial region to the higher eentrer, 5-HTergic or SPergic terminals may exert some modulatory effects directcy and iudirectly through regulating the activity of the GABAergic Vine interneurons.