SYNAPTIC POTENTIATION OF DUAL-COMPONENT EXCITATORY POSTSYNAPTIC CURRENTS IN THE RAT HIPPOCAMPUS
SYNAPTIC POTENTIATION OF DUAL-COMPONENT EXCITATORY POSTSYNAPTIC CURRENTS IN THE RAT HIPPOCAMPUS
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DOI：
10.1113/jphysiol.1995.sp020498
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发表时间：
1995-01-01
影响因子：
5.5
通讯作者：
COLLINGRIDGE, GL
中科院分区：
文献类型：
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作者：
CLARK, KA;COLLINGRIDGE, GL
1.采用全细胞膜片钳技术研究了阻断GABA（A）和GABA（B）受体介导的突触抑制后，强直刺激诱导的大鼠海马脑片CA 1区双成分兴奋性突触后电流（EPSC）的突触增强.在-60 mV的保持电位下，EPSC的初始斜率（最大振幅的10%至60%之间）提供了AMPA受体介导的成分的准确测量，并且在100 ms的潜伏期下EPSC的振幅提供了NMDA受体介导的成分的大小的最佳估计。神经元在递送强直之前电压钳位至少45分钟（测试强度，100 Hz，1 s）。破伤风后10和30分钟的测量分别用作短时程增强（STP）和长时程增强（LTP）的指示。一组神经元始终在-60 mV下进行电压钳位。根据AMPA受体介导的成分是否存在LTP（n = 9）或仅存在STP（n = B），这些神经元可被细分为两个群体。第二组神经元在强直刺激之前、期间和之后在-60 mV电压钳位30 min，然后在-50 mV电压钳位15 min。在这些实验中，存在STP，但不存在LTP（n = 8）。在所有的神经元（n = 23），增强的NMDA受体介导的组件的时间过程中，AMPA受体介导的组件的。此外，NMDA和AMPA受体介导的成分的增强具有相似的幅度。这些数据表明，在全细胞记录45分钟后，高频刺激可以诱导LTP。在这些条件下，存在AMPA和NMDA受体介导的双组分EPSC组分的平行增强。这构成了第一个证据，从研究的双组分突触反应，这是一致的突触前位点的表达破伤风诱导的STP和LTP在海马。
1. Whole-cell patch-clamp recording has been used to study tetanus-induced synaptic potentiation of dual-component excitatory postsynaptic currents (EPSCs) in the CA1 region of rat hippocampal slices, following blockade of GABA(A) and GABA(B) receptor-mediated synaptic inhibition.2. At a holding potential of -60 mV, the initial slope of the EPSC (between 10 and 60% of maximum amplitude) provided an accurate measurement of the AMPA receptor-mediated component, and the amplitude of the EPSC at a latency of 100 ms provided the best estimate of the size of the NMDA receptor-mediated component.3. Neurons were voltage clamped for at least 45 min prior to delivery of a tetanus (test intensity, 100 Hz, 1 s). Measurements at 10 and 30 min following the tetanus were used as indications of short-term potentiation (STP) and long-term potentiation (LTP), respectively. One set of neurons were voltage clamped at -60 mV throughout. These neurons could be subdivided into two populations on the basis of whether or not there was LTP (n = 9), or only STP (n = B), of the AMPA receptor-mediated component. A second set of neurons were voltage clamped at -60 mV for 30 min and then at -50 mV for 15 min before, during and for 30 min following tetanization. In these experiments there was STP but not LTP (n = 8).4. In all neurons (n = 23), the time course of the potentiation of the NMDA receptor-mediated component paralleled that of the AMPA receptor-mediated component. In addition, potentiation of the NMDA and AMPA receptor-mediated components were of a similar magnitude.5. These data demonstrate that it is possible to induce LTP by high frequency stimulation after 45 min of whole-cell recording. Under these conditions, there is a parallel potentiation of the AMPA and NMDA receptor-mediated components of dual-component EPSCs. This constitutes the first evidence, from studies of dual-component synaptic responses, which is consistent with a presynaptic locus of expression of tetanus-induced STP and LTP in the hippocampus.