文章摘要
徐金东,夏明媚,盛 涛,朱东亚.氧糖剥夺引起MF-CA3通路突触传递LTD现象及其机制研究[J].南京医科大学学报,2015,(6):761~765
氧糖剥夺引起MF-CA3通路突触传递LTD现象及其机制研究
Oxygen/glucose deprivation induces LTD at MF-CA3 synapses
投稿时间:2015-01-28  
DOI:10.7655/NYDXBNS20150601
中文关键词: 氧糖剥夺  突触传递减弱  AMPA受体  代谢型谷氨酸受体  钙离子
英文关键词: oxygen/glucose deprivation  LTD  AMPARs  mGluR  Ca2+
基金项目:国家自然科学基金(81030023)
作者单位
徐金东 南京医科大学药学院药理实验室,江苏 南京 210029 
夏明媚 东南大学生命科学院,江苏 南京 210008 
盛 涛 东南大学生命科学院,江苏 南京 210008 
朱东亚 南京医科大学药学院药理实验室,江苏 南京 210029 
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中文摘要:
      目的:观察氧糖剥夺引起的MF-CA3通路突触传递的长时程抑制(long-term depression, LTD)现象,并探讨其分子机制。方法:选择出生后2~3周的Sprague Dawley(SD)乳大鼠,制备海马脑片,通过刺激苔藓纤维,采用膜片钳的方法记录突触后电流。氧糖剥夺15 min后,观察突触传递的变化情况。分别采用犬尿喹啉酸阻断α-氨基羟甲基恶唑丙酸(α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid,AMPA)受体?LY341495阻断代谢型谷氨酸受体﹑BAPTA螯合细胞内钙离子,观察对LTD的可能影响。结果:①氧糖剥夺15 min能引起MF-CA3通路AMPA受体介导的突触电流减弱,产生LTD现象;②若氧糖剥夺过程中运用阻断剂阻断AMPA受体的激活,洗脱后并不影响LTD的产生,而阻断代谢型谷氨酸受体可以使AMPA受体电流的LTD现象消失;③除去外液中的钙离子或用BAPTA螯合细胞内的钙离子均能使LTD现象消失。结论:氧糖剥夺引起MF-CA3通路上AMPA受体介导的突触电流持续减弱,呈现LTD现象。这种LTD现象依赖于代谢型谷氨酸受体的激活及胞内外钙离子浓度升高,但不依赖氧糖剥夺过程中AMPA受体的激活。
英文摘要:
      Objective:To observe oxygen/glucose deprivation (OGD) induced long-term depression (LTD) during synaptic transmission at mossy fiber to CA3 (MF-CA3) synapses and to study the underlying mechanisms. Methods: Sprague Dawley (SD) newborn rats of 2-3 weeks after birth were selected for hippocampal slices. We performed whole-cell patch-clamp recording on CA3 pyramidal neurons and monitored evoked excitatory postsynaptic currents (EPSCs) at MF-CA3 synapses upon mossy fiber stimulation. After 15-min of OGD, we observed the changes of synaptic transmission. We also co-applied blockers of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptors (AMPARs, which blocked by kynurenic acid), metabotropic glutamate receptors (mGluRs, which blocked by LY341495) or calcium chelator during OGD treatment to examine whether OGD-induced alteration in synaptic transmission requires activation of these receptors or increase of calcium. Results:①15-min OGD induced LTD of AMPA receptor (AMPAR)-mediated synaptic transmission at MF-CA3 synapses. ②OGD-induced LTD of AMPAR-mediated responses was dependent on activation of mGluRs but not of AMPARs. ③Removal of Ca2+ from ACSF during OGD or inclusion of Ca2+ chelator BAPTA to the patch pipette solution abolished LTD. Conclusion: OGD induces LTD of AMPAR-mediated synaptic responses at MF-CA3 synapses. This synaptic plasticity requires activation of mGluRs and intracellular Ca2+ increase without AMPARs.
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