ISSN 0371-0874, CN 31-1352/Q

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生理学报 2010; 62(1): 23-29

晚时相长时程增强翻转前后大鼠海马CA1区AMPAR/GluR2的表达

张莉, 李延海, 孟凯, 谢雯

西安交通大学 医学院生理学与病理生理学系； 环境与疾病相关基因教育部重点实验室，西安 710061； 生命科学院生物医学工程系，西安 710049

摘要

晚时相长时程增强 (late-phase long-term potentiation，L-LTP)对于海马长期记忆的维持具有非常重要的作用，然而L-LTP 可被诱导之后的神经元活动所翻转。本实验旨在研究海马CA1 区L-LTP 的翻转是否有突触前机制的参与以及L-LTP翻转前后AMPARs 的表达有无变化。实验采用海马脑薄片细胞外场电位记录技术，使用强直刺激 (high-frequency stimulation,HFS)诱导出CA1 区L-LTP，2 h 后用两组间隔10 min 的高强度的双脉冲低频刺激(high-intensity paired-pulse low frequencystimulation, HI-PP-LFS)诱导L-LTP 翻转。在LTP 诱导前、诱导2 h 后、翻转后均给予一个双脉冲刺激，观察双脉冲比值(paired-pulse ratio, PPR)的变化；另一方面，实验通过免疫荧光组织化学方法观察AMPAR/GluR2 在L-LTP 翻转前后海马CA1 区表达的变化。结果显示，L-LTP 诱导后2 h，HI-PP-LFS 可诱导L-LTP 的部分翻转(翻转率为61.79%±14.51%)。LTP诱导前、诱导2 h 后、翻转后PPR 均大于1，表现为双脉冲易化(paired-pulse facilitation, PPF)，且三者大小顺序为：LTP诱导后 < LTP 翻转后 < LTP 诱导前；在海马CA1 区AMPAR/GluR2 亚单位的表达方面，对照组、LTP 组及LTP 翻转组之间没有显著差异。上述结果提示，海马CA1 区L-LTP 维持与翻转均有突触前机制的参与，但L-LTP 诱导与翻转前后AMPAR/GluR2 表达没有发生变化。

关键词： L-LTP; LTP 翻转; AMPARs/GluR2; 海马

分类号：Q426; R338

[AMPAR/GluR2 in hippocampal CA1 area of rats before andafter late-phase long-term potentiation reversal.] [Ariticle in Chinese]

ZHANG Li, LI Yan-Hai, MENG Kai, XIE Wen

Department of Physiology and Pathophysiology, Medical School of Xi’an Jiaotong University； Ministry of Education Key Laboratoryof Environment and Gene Related Diseases, Xi’an Jiaotong University, Xi’an 710061, China； Institute of BiomedicalEngineering, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China

Abstract

Late-phase long-term potentiation (L-LTP) plays a very important role in the maintenance of long-term memory inhippocampus. However, studies have shown that L-LTP can be reversed by subsequent neuronal activity. The aim of the present studyis to investigate whether the presynaptic mechanism and the change of AMPARs expressions are involved in the reversal of L-LTP inhippocampal CA1 area. Standard extracellular recording technique was used to record the potential change in the stratum radiatum ofCA1 area of adult rat hippocampal slices. Two hours after LTP induction, which was induced by high-frequency stimulation (HFS),two episodes of high-intensity paired-pulse low-frequency stimulation (HI-PP-LFS) were delivered to induce L-LTP reversal. Pairedpulseratios (PPR) were obtained before LTP induction, 2 h after LTP induction and 30 min after LTP reversal. On the other hand,immunofluorescence histochemistry was used to detect AMPARs expressions before and after L-LTP reversal. The results showed that, after 2 h of induction, L-LTP was partially reversed by two episodes of HI-PP-LFS, and the percentage of depotentiation was 61.79%±14.51%. PPR obtained before and after LTP induction, and as well that after LTP reversal, are all more than 1, showing paired-pulsefacilitation (PPF). Multiple comparison indicated PPR before LTP induction was the greatest one, and PPR after LTP induction was thesmallest. In addition, no significant difference was observed in the intensity of AMPAR/GluR2 immunoreactivity in CA1 area amongcontrol group, LTP group and LTP reversal group. These results suggest that the presynaptic mechanism is involved in both themaintenance and reversal of L-LTP and there is no change in AMPAR/GluR2 expression before and after the reversal of L-LTP.

Key words: L-LTP; LTP reversal; AMPARs/GluR2; hippocampus

收稿日期：2009-08-05　　录用日期：2009-12-04

通讯作者：张莉　　E-mail: shuchengan@snnu.edu.cn

引用本文：

张莉, 李延海, 孟凯, 谢雯. 晚时相长时程增强翻转前后大鼠海马CA1区AMPAR/GluR2的表达[J]. 生理学报 2010; 62 (1): 23-29.

ZHANG Li, LI Yan-Hai, MENG Kai, XIE Wen. [AMPAR/GluR2 in hippocampal CA1 area of rats before andafter late-phase long-term potentiation reversal.] [Ariticle in Chinese] . Acta Physiol Sin 2010; 62 (1): 23-29 (in Chinese with English abstract).

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