刺激延髓背角诱发的小鼠脑干网状结构内向Vmo投射的GABA能神经元突触后反应的电生理学研究  

Electrophysiological research on medullary dorsal horn stimulation-evoked postsynaptic responses of GABAergic neurons projecting to the Vmo in reticular formation of brainstem in mouse

作　　者：葛顺楠[1,2] 陈涛[1] 牛乐[1] 武胜昔[1] 李金莲[1] 高国栋[2] 

机构地区：[1]第四军医大学人体解剖学教研室暨梁銶琚脑研究中心,西安710032 [2]第四军医大学唐都医院神经外科,西安710032

出　　处：《神经解剖学杂志》2008年第6期597-601,共5页Chinese Journal of Neuroanatomy

基　　金：国家自然科学基金(No.30570980);国家教育部创新团队发展计划(IRT0560)资助项目

摘　　要：本实验利用谷氨酸脱羧酶67-绿色荧光蛋白(GAD67-GFP)基因敲入小鼠制备离体脑片,结合TMR逆行束路追踪技术,在荧光镜和红外镜头下,利用膜片钳全细胞记录的方法对电刺激延髓背角(即三叉神经脊束核尾侧亚核,Vc)诱发的小鼠小细胞网状结构(PCRt)内GABA能和TMR逆标的运动前神经元的突触后反应及其反应类型、药理学特征进行系统的研究。结果显示:(1)高频刺激(20 Hz)Vc,在PCRt内GFP和TMR双标的运动前神经元上可记录到兴奋性的突触后电流(EP-SCs),波形显示为单突触反应;(2)电压钳记录模式下,α-氨基羟甲基恶唑丙酸受体(AMPA受体)拮抗剂氨基-2-硝基喹啉-2,3-二酮(CNQX)及N-甲基-D-天冬氨酸受体(NMDA受体)阻断剂D,L-2-氨基-5-磷酸基戊酸(AP-5)均可显著降低刺激Vc所诱发的小鼠PCRt内GFP和TMR双标神经元的EPCSs的幅值;(3)电流钳模式下,刺激Vc,在PCRt内GFP和TMR双标的神经元上记录到兴奋性突触后电位,其幅度与刺激强度在一定范围内呈正相关。以上结果提示,小鼠PCRt内向三叉神经运动核(Vmo)发出投射的GABA能运动前神经元可通过其细胞膜上AMPA受体或NMDA受体的介导,对口面部伤害性信息发挥整合和调控作用,以实现对口面部伤害性反射活动的精确调节。In the present study, we made in vitro brain slices of glutamate decarboxylase67-GFP （GAD67-GFP） knock-in mouse, combining TMR retrograde tracing method, under the fluorescope and infrared lens, the postsynaptic responses of GABAergic and TMR retrograde labeled neurons in the parvocellular reticular formation（PCRt） evoked by medullary dorsal horn （ also called caudal spinal trigeminal nucleus, Vc） electrical stimulation, as well as the pattern of the responses and its pharmacological properties, were studied systematically by patch-clamp method in the mode of whole-cell recording. The results showed that： （ 1 ） High frequency stimulation （20 Hz） of the Vc can evoke excitatory postsynaptic currents （EPSCs） of double GFP- and TMR-labeled premotor neurons in PCRt and waveform proved it to be monosynaptic responses; （2）Using voltage clamp research, the administration of antagonist of AMPA receptor-CNQX and antagonist of NMDA receptor-AP-5 can significantly decrease the amplitude of EPSCs of double GFP- and TMR-labeled premotor neurons in PCRt evoked by Vc stimulation; （3） Using current clamp research, Vc stimulation can evoke excitatory postsynaptic potential in the double GFP- and TMR-labeled premotor neurons in PCRt and there is positive correlation between the amplitude and stimulus intensity in a certain range. The above results suggest that GABAergic premotor neurons projecting to the trigeminal motor nucleus （Vmo） in PCRt might have integration and control effects mediated by APMA or NMDA receptors for the orofacial nociceptive informations, and carry out precise regulation on the orofacial nociceptive reflexes.

关 键 词：γ-氨基丁酸 膜片钳 全细胞记录 运动前神经元 延髓背角 网状结构 GAD67-GFP基因敲入小鼠 

分 类 号：R33[医药卫生—人体生理学]