幼年非洲爪蟾视顶盖区突触前、后膜上受体间的相互作用  

The Interaction between synaptic glutamatergic receptors and GABAergic receptors in optic tectum of juvenile Xenopus

作　　者：刘燕[1] 温晓红[1] 管永清[2] 蔡浩然[1] 

机构地区：[1]北京大学第一医院中心实验室,北京100034 [2]河北医科大学第四医院眼科,河北石家庄050011

出　　处：《中国神经科学杂志》2004年第6期411-415,共5页

基　　金：国家自然科学基金 (3 9670 774);河北省科技项目 (0 2 2 7610 3D 14 )

摘　　要：目的　 记录幼年非洲爪蟾视顶盖区第六层神经元的自发性微突触后电流 (mPSCs)。 方法 　应用盲法电压膜片钳全细胞记录技术。 结果　 观察到用谷氨酸受体激动剂NMDA灌流脑片后先引起mIPSCs的频率明显增加并出现内向膜电流及高频的mEPSCs,经一段时间洗脱后mIPSCs和mEPSCs又均完全消失 ,而膜电流恢复到原来未加NMDA前的水平。GABA受体的激动剂GABA可诱发明显的外向膜电流。GABAa受体拮抗剂荷包牡丹碱 (bicucullin ,BM)不仅能将mIPSCs全部抑制掉 ,并且还可以诱发mEPSCs。谷氨酸受体的拮抗剂APV对mPSCs亦有类似的作用 ,不仅可以抑制顶盖神经元的mEPSCs,而且可以使原有的mIPSCs的频率和振幅均增加。 结论　幼年期的突触前、后膜上既有兴奋性谷氨酸能受体也有抑制性γ 氨基丁酸能受体 ,而且在突触前膜上受体可以调制突触末梢神经递质的释放。因此突触前、后膜上的受体间存在相互作用 ,以确保突触前后活动和功能上的稳定 ,从而达到神经网络的平衡。Objective To explore the interaction between synaptic glutamatergic receptors and GABAergic receptors in optic tectum of juvenile Xenopus,spontaneous miniature postsynaptic currents (mPSCs) were recorded. Method By using the blind patch-clamp technique with whole-cell mode. Results Glutamatergic receptor agonist NMDA could increase the frequency of mIPSCs. It was also observed that the membrane current appeared to be shifted toward inward direction and higher frequency of mEPSCs were evoked. Outward membrane current was elicited by exogenous GABA. In some experiments, it had been shown that bicuculline (BM), an antagonist of GABAa receptor, could not only inhibit mIPSCs, but also evoke mEPSCs; APV, an antagonist of NMDA receptor, could increase the frequency and amplitude of mIPSCs. It is suggested that there are two kinds of synaptic receptors: excitatory glutamatergic receptor and inhibitory GABAergic receptor in optic tectum of juvenile Xenopus. Conclusion These receptors are interacted each other in the normal conditions, one kind of which may play a dominant role in the synaptic activities in various situations. NMDA receptors are fundamental for neuronal plasticity and development in the central nervous system. In our study, it was confirmed that on the presynaptic terminals there were excitatory glutamatergic receptor and inhibitory GABAergic receptor and they were interacted each other to control the stability of the nerve network.

关 键 词：微突触后电流 受体 相互作用 膜片钳 脑片 

分 类 号：Q429[生物学—神经生物学]