Maggio Nicola, Shavit Stein Efrat, Segal Menahem
Talpiot Medical Leadership Program, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Hippocampus. 2015 Nov;25(11):1465-71. doi: 10.1002/hipo.22467. Epub 2015 Jun 19.
A transient ischemic episode causes a reduction in evoked EPSPs in hippocampal slices, followed by an NMDA dependent LTP. We explored the relations between ischemic LTP (iLTP) and the more conventional tetanic LTP (tLTP) in CA1 region of slices along the dorsal/ventral axis of the hippocampus. Dorsal hippocampal (DH) slices produced a much larger iLTP than their ventral hippocampal (VH) counterparts. In both regions, iLTP and tLTP shared the same NMDA mediated potentiation, such that one LTP saturated the ability of the other treatment to generate LTP. The smaller LTP in VH was correlated with a lower NMDA-mediated EPSP, and a parallel lower density of NMDA receptors. Calcium permeable AMPA receptors did not contribute to the DH/VH disparity. We conclude that a differential distribution of NMDA receptor subunits along the septotemporal axis of the hippocampus controls the diverse ability to evoke iLTP and tLTP in the two regions and may underlie their characteristic behavioral outputs as well as their differential sensitivity to ischemia.
短暂性缺血发作会导致海马切片中诱发的兴奋性突触后电位（EPSP）降低，随后出现依赖N-甲基-D-天冬氨酸（NMDA）的长时程增强（LTP）。我们沿着海马体的背侧/腹侧轴，探究了切片CA1区缺血性LTP（iLTP）与更传统的强直刺激LTP（tLTP）之间的关系。背侧海马（DH）切片产生的iLTP比腹侧海马（VH）切片大得多。在这两个区域，iLTP和tLTP都共享相同的NMDA介导的增强作用，以至于一种LTP会饱和另一种处理产生LTP的能力。VH中较小的LTP与较低的NMDA介导的EPSP以及平行的较低密度的NMDA受体相关。钙通透性α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）受体对DH/VH差异没有影响。我们得出结论，NMDA受体亚基沿海马体的隔颞轴的差异分布控制了两个区域诱发iLTP和tLTP的不同能力，并且可能是它们特征性行为输出以及对缺血的不同敏感性的基础。
