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低频刺激后海马CA1区场兴奋性突触后电位与群体锋电位的变化

梁华为, 沈岳良, 陈志雄, 夏强

浙江大学医学院生理学教研室.浙江,杭州 310031

摘要

在大鼠海马脑片上使用双电极在CA1区进行细胞外记录,观察低频刺激(LFS)诱发同突触长时程抑制(LTD)时场兴奋性突触后电位(fEPSP)的斜率(S-EPSP)和群体锋电位(PS)的幅值(A-PS)的变化。给予900脉冲1Hz LFS后,S-EPSP和A-PS降低的幅度分别是35.4±5.3%和68.0±7.2%;而给予450脉冲1Hz LFS后,S-EPSP和A-PS分别降低14.3±2.3%和36.8%±6.7%。上述两组中A-PS的变化率均显著大于S-EPSP(P<0.01),而900脉冲数组中两个指标的变化率均大于450脉冲数组(P<0.05)。高Mg~(2+)(4mmol/L)使突触 的传递活动减弱,但不影响LTD的诱发,在高Mg~(2+)介质中,LFS引起的A-PS变化率仍显著大于S-EPSP(P<0.01)。结果表明,由LFS诱发同突触LTD的水平不仅与LFS的脉冲数有关,还与评价指标的选择有关。

关键词： 突触可塑性; 长时程抑制; 海马

Changes in field excitatory postsynaptic potential and population spike in CA1 region of rat hippocampal slices following low-frequency stimulation

Liang Huawei, Shen Yueliang, Chen Zhixiong, Xia Qiang

Department of Physiology,Zhejiang University School of Medicine.Hangzhou 310031,Zhejiang

Abstract

The technique of extracellular recording was used and the changes in the slope of field excitatory postsynaptic potential (S-EPSP) and the amplitude of population spike (A-PS) were observed when homosynaptic long-term depression (LTD) was induced by low-frequency stimulation (LFS) in the CA1 region of rat hippocampal slices. After LFS of 900 pulses at 1 Hz was delivered, S-EPSP and A-PA were reduced by 35.4+-5.3% and 68.0+-7.2%, respectively. When LFS of 450 pulses at 1 Hz was delivered, S-EPSP and A-PS were reduced by 14.3+-2.3% and 36.8+-6.7%, respectively. In both groups, the change in A-PS was significantly greater than that in S-EPSP (P<0.01). The changes in both indexes in the group of 900 pulses were greater than those in the group of 450 pulses (P<0.05). High Mg~(2+) (4 mmol/L) could attenuate the synaptic transmission, but did not affect the induction of LTD. In the high Mg~(2+) medium, the change in A-PS induced by LFS was also markedly greater than that in S-EPSP (P<0.01). These results indicate that the level of homosynaptic LTD indued by LFS is dependent not only on the numbers of pulses of LFS delivered, but also on the selection of evaluating index.

Key words: Synaptic plasticity;Long-term depression;Hippocampus

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引用本文：

梁华为, 沈岳良, 陈志雄, 夏强. 低频刺激后海马CA1区场兴奋性突触后电位与群体锋电位的变化[J]. 生理学报 2002; 54 (5): .

Liang Huawei, Shen Yueliang, Chen Zhixiong, Xia Qiang. Changes in field excitatory postsynaptic potential and population spike in CA1 region of rat hippocampal slices following low-frequency stimulation. Acta Physiol Sin 2002; 54 (5): (in Chinese with English abstract).