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脑缺血大鼠缺血同侧海马齿状回突触可塑性的变化

hange in the synaptic plasticity of ischemic hippocampal dentate gyrus in the rat with focal cerebral ischemia

中文摘要英文摘要

目的:观察缺血性脑损伤对缺血同侧海马齿状回突触可塑性的影响。 方法:实验于2005年6月-2005年8月在中国科技大学生命科学院神经毒理实验室完成。24只雄性Wistar 大鼠分为假手术2周组和缺血2周组两组,采用热凝闭大鼠大脑中动脉致局灶性脑缺血模型,观察缺血性脑损伤对缺血同侧海马齿状回突触可塑性的影响。 结果:缺血2周后缺血同侧海马齿状回兴奋性突触后电位的I/O曲线幅度显著降低 (P<0.05),群峰电位的I/O曲线幅度也显著降低(P<0.05);兴奋性突触后电位的长时程增强幅度在假手术组为109±3.8%,缺血2周后升高为114±1.9% (P<0.05)。群峰电位的长时程增强幅度在假手术组为201±13%,而在缺血组群峰电位的长时程增强幅度明显降低为179±13% (P<0.05);兴奋性突触后电位的长时程抑制幅度在假手术组为98.7±3.4%,缺血2周后明显降低为89±3.5% (P<0.05)。群峰电位的长时程抑制幅度在假手术组为84.7±5.3%,而在缺血组群峰电位的长时程抑制幅度为85.6±3.9%,与假手术组无明显区别 (P>0.05)。 结论:脑缺血降低了海马齿状回区基本的突触传递,同时降低单脉冲刺激海马穿通纤维引起的齿状回颗粒细胞的共同发放幅度;缺血损伤了海马齿状回区群峰电位的长时程增强诱导,而对兴奋性突触后电位的长时程增强诱导有促进作用;缺血损伤了海马齿状回区兴奋性突触后电位的长时程抑制诱导,而对群峰电位的长时程抑制诱导没有明显影响。

IM:To observe the effect of focal cerebral ischemia on synaptic plasticity in the rat dentate gyrus . METHODS: Totally 24 male adult Wistar rats were divided into 2 groups: sham-operated 2 weeks group and ischemia 2 weeks group. Models of focal cerebral ischemia were established by heat coagulating occlusion of the middle cerebral artery. The changing of synaptic plasticity in the rat dentate gyrus were studied 2 weeks after ischemia. RESULTS: Compared with the control rats the current-voltage curve of EPSP slope in ischemia rate was significant depressed (P<0.05),Ischemia reduced the amplitudes of the I/O curve of PS (P<0.05) significantly. The amplitudes of PS LTP was also reduced by ischemia(control: 201±13%,n=6;ischemia:179±13%,n=6, P<0.05),The amplitudes of EPSP LTP was enhanced by ischemia(control: 109±3.8%,n=6;ischemia: 114±1.9%,n=6, P<0.05). The amplitudes of EPSP LTD was also reduced by ischemia(control: 98.7±3.4%,n=6;ischemia: 89±3.5%,n=6, P<0.05). The amplitudes of PS LTD had not significantly difference between control and ischemia (control: 84.7±5.3%,n=6;ischemia: 85.6±3.9%,n=6, P>0.05). CONCLUSION:The result may imply that ischemia affected baseline synapic transmission evoked by single-shock perforant path stimulation in area DG of hippocampus and influence to synchronous firing of many dentate granule cells.These results demonstrated that ischemia impaired the induction of PS LTP and EPSP LTD in area DG of hippocampus in vivo.The ischemia enhanced the induction of EPSP LTP,but PS LTD had not significantly difference between control and ischemia.

靳瑞、许能贵、易玮、徐振华

基础医学神经病学、精神病学生理学

脑缺血齿状回突触大鼠

erebral IschemiaSynaptic PlasticityRats

靳瑞,许能贵,易玮,徐振华.脑缺血大鼠缺血同侧海马齿状回突触可塑性的变化[EB/OL].(2007-12-12)[2025-08-18].http://www.paper.edu.cn/releasepaper/content/200712-198.点此复制

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