摘要
目的：了解正常年轻大鼠穿通路－海马齿状回突触的功能可塑性，为研究脑衰老对学习记忆的影响及其神经机理奠定工作基础。方法：应用细胞外微电极记录电刺激穿通路在海马齿状回诱发的群体锋电位（ＰＳ），观察高频刺激（ＨＦＳ）及双脉冲刺激后ＰＳ幅值变化。结果：ＨＦＳ后，１８例鼠中１５例ＰＳ幅值明显增强，平均达基线值的（１４８．５±１２．５）％，其中１０例为长时程增强，５例为短时程增强。１例于ＨＦＳ后ＰＳ幅值减小，仅为基线值的５３％，为长时程抑制。２例ＨＦＳ前后ＰＳ无变化；双脉冲刺激时，１４例鼠中１３例发生双脉冲易化，１例发生双脉冲抑制。结论：正常年轻大鼠海马穿通路－海马齿状回突触的传递功能在高频和双脉冲刺激后可发生以长时程增强和双脉冲易化为主的可塑性变化。
Objective: In order to investigate the nervous mechanism and the effect of brain aging on learning and memory, we observed the expressive forms of synaptic functional plasticity of the perforant path (PP)hippocampal dentate gyrus (DG) in health young rats in vivo. Methods: The population spike (PS) evoked by single pulse stimulating the PP was recorded from DG with extracellular microelectrode. Following a period of the PS baseline recordings about 30 minutes, highfrequency stimulation at 100/sec for 5 seconds (HFS) was delivered. Testing with single pulse was continued for 1～2 hours after HFS. Then pairedpulse stimulation was applied with different interstimulus intervals (ISIs). Results: In 18 rats, the mean PS amplitude and peak latency before HFS was 0.87±0.12 mV and 12.5±0.98 ms respectively. After HFS, amplitudes of the PS were potentiated in 15 rats with a mean increase in relation to baseline amplitude to (148.5±12.5)%. In 10 out of these rats, the longterm potentiation (LTP) was induced, the time course of LTP lasted from 30 minutes to 4 hours after the HFS. In other 5 rats for less than 30 minutes, they were called as shortterm potentiation (STP). In one rat, the longterm depression (LTD) was induced after HFS, their time course lasted for 50 minutes. In two rats, no changes were found in PS amplitudes after HFS. In 14 rats, the effect of pairedpulse stimulating (PPS) the PP on the PS amplitude was examined. In 13 of 14 rats, the pairedpulse facilitation occurred, but in the other one the pairedpulse depression did.Conclusions: The present study shows that main in vivo expressive forms of PPDG synaptic functional plasticity after HFS and PPS in health young rat were LTP and pairedpulse facilitation.
出处
《中国医科大学学报》
CAS
CSCD
北大核心
1998年第2期114-118,共5页
Journal of China Medical University
基金
卫生部科研基金
关键词
长时程增强
突触可塑性
在体电生理
电生理
longterm potentiation
pairedpulse facilitation
synaptic plasticity
hippocampus
rat
