An intracellular study of pretectal influence on the optic tectum of the frog, Rana catesbeiana  

青蛙前视盖与视顶盖间神经传导的细胞内电生理研究(英文)

作　　者：康宏建[1] 李晓红[1] 

机构地区：[1]日本九州工业大学生命体大学院脑研究中心

出　　处：《Neuroscience Bulletin》2007年第2期113-118,共6页神经科学通报（英文版）

摘　　要：Objective A few investigations have been reported about pretectal suppressive influences on the optic tectum of frog, but characteristics of tectal activity to pretectal input are left unknown. We made intracellular recordings to demonstrate the unexpected complexity in synaptic mechanisms involved in the suppressive influences of pretecal stimulation on the tectal cells. Methods In the present study, we investigated the neuronal activity evoked by pretectal （Lpd/P） nuclei stimulation using intracellular recording technique. Results The pretectal stimulation mainly elicited two types of responses in the ipsilateral tectum： an excitatory postsynaptic potential （EPSP） followed by an inhibitory postsynaptic potential （IPSP） and a pure IPSP. The latter predominated in the tectal cells responding to pretectal stimulation. In a few cells, biphasic hyperpolarization appeared under stronger stimulus intensities. The spikes of tecto-pretectal projecting cells elicited by antidromical stimulation were recorded in the ipsilateral tectum, which revealed reciprocal connections between the tectum and particular pretectal nuclei. The synaptic natures underlying pretecto-tectal information transformation have also been demonstrated. EPSPs with short latencies were concluded to be monosynaptic. Most IPSPs were generated through polysynaptic paths, but monosynaptic IPSPs were also recorded in the tectum. Nearly 98% of impaled tectal cells （except for antidromically projecting cells） showed inhibitory responses to pretectal stimulation. Conclusion The results provide strong evidence that pretectal cells broadly inhibit tectal neurons as that has suggested by behavioral and extracellular recording studies.目的已有许多研究报告了青蛙的前视盖对视顶盖起抑制作用,但关于此神经活动的特性尚不清楚。本研究探讨了这种复杂的神经活动的机理。方法用细胞内记录方法,通过电刺激前视盖的神经细胞核来记录视顶盖细胞的神经活动。结果前视盖的电刺激在同侧视顶盖主要唤起了两种神经反应:一种是兴奋性(excitatory postsynaptic potential,EPSP)和抑制性突触后电位(an inhibitory postsynaptic potential,IPSP)同时出现,另一种是单纯的IPSP,后者在本记录中占主导地位。另外我们也记录到了某些投射到前视盖的视盖投射细胞的神经电位。它揭示了视顶盖和前视盖之间存在着交叉性的相互作用。短潜时的EPSP可能是通过单突触进行传导的,而大多数的IPSP是通过多突触方式进行神经信息传递的。几乎98%被记录的视盖细胞对前视盖的刺激显示出了抑制性反应。结论前视盖的神经细胞对视顶盖的神经活动发挥了强烈的抑制性作用。

关 键 词：electric stimulation optic tectum Rana catesbeiana 

分 类 号：Q42[生物学—神经生物学]