EPSPs in rat neocortical neurons in vitro. I. Electrophysiological evidence for two distinct EPSPs.
EPSPs in rat neocortical neurons in vitro. I. Electrophysiological evidence for two distinct EPSPs.
复制标题
体外大鼠新皮质神经元中的 EPSP。
DOI：
10.1152/jn.1989.61.3.607
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发表时间：
1989
影响因子：
2.5
通讯作者：
Hablitz,JJ
中科院分区：
文献类型：
--
作者：
Sutor,B;Hablitz,JJ
1.对大鼠内侧额叶皮质II/III层神经元进行细胞内记录，研究兴奋性突触后电位。神经元的平均静息膜电位大于-75 mV，平均输入电阻大于20M omega。注入去极化电流脉冲诱发的动作电位幅度大于100 mV。记录到的神经元的电生理特性与规则棘突锥体细胞的特性相似。2.由注入内向和外向电流脉冲确定的电流-电压关系，在去极化和超极化方向上都表现出相当大的向内整流。稳态输入电阻随膜时间常数的增大而增大，随膜时间常数的增大而减小，随超极化的增大而减小。3.通过位于新皮质IV层的双极电极，电刺激诱发突触后电位。通过逐渐增加刺激强度确定的刺激-反应关系在被检查的神经元群体中是一致的。短潜伏期EPSP[早期EPSP(EEPSP)]是阈值最低的反应。EEPSP的波幅为4~8 mV。膜电位超极化后，eEPSP的幅度降低。在去极化时，观察到幅度和持续时间略有增加，同时达到峰值的时间显著增加。4.用单电极电压钳方法测定了eEPSP(EEPSC)膜电流。在所测试的12个神经元中，有8个神经元的eEPSC波幅明显不依赖于膜电位。在其余4个神经元中，eEPSC的波幅随超极化的增加而增加，随去极化而降低。5.较高的刺激强度除诱发eEPSP外，还可在90%以上的受试者中诱发延迟EPSP[晚期EPSP(LEPSP)]。LEPSP波幅12~20 mV，潜伏期20~60ms。LEPSP的幅度随膜电位的变化而变化，随去极化而减小，随超极化而增大。LEPSP(LEPSC)下的膜电流表现出类似的电压依赖关系。6.在导致抑制性突触后电位(IPSP)激活的刺激强度下，不再观察到lEPSP。
1. To investigate excitatory postsynaptic potentials (EPSPs), intracellular recordings were performed in layer II/III neurons of the rat medial frontal cortex. The average resting membrane potential of the neurons was more than -75 mV and their average input resistance was greater than 20 M omega. The amplitudes of the action potentials evoked by injection of depolarizing current pulses were greater than 100 mV. The electrophysiological properties of the neurons recorded were similar to those of regular-spiking pyramidal cells. 2. Current-voltage relationships, determined by injecting inward and outward current pulses, displayed considerable inward rectification in both the depolarizing and hyperpolarizing directions. The steady-state input resistance increased with depolarization and decreased with hyperpolarization, concomitant with increases and decreases, respectively, in the membrane time constant. 3. Postsynaptic potentials were evoked by electrical stimulation via a bipolar electrode positioned in layer IV of the neocortex. Stimulus-response relationships, determined by gradually increasing the stimulus intensity, were consistent among the population of neurons examined. A short-latency EPSP [early EPSP (eEPSP)] was the response with the lowest threshold. Amplitudes of the eEPSP ranged from 4 to 8 mV. Following a hyperpolarization of the membrane potential, the amplitude of the eEPSP decreased. Upon depolarization, a slight increase in amplitude and duration was observed, accompanied by a significant increase in time to peak. 4. The membrane current underlying the eEPSP (eEPSC) was measured using the single-electrode voltage-clamp method. The amplitude of the eEPSC was apparently independent of the membrane potential in 8 of 12 neurons tested. In the other 4 neurons, the amplitude of the eEPSC increased with hyperpolarization and decreased with depolarization. 5. Higher stimulus intensities evoked, in addition to the eEPSP, a delayed EPSP [late EPSP (lEPSP)] in greater than 90% of the neurons tested. The amplitude of the lEPSP ranged from 12 to 20 mV, and the latency varied between 20 and 60 ms. The amplitude of the lEPSP varied with membrane potential, decreasing with depolarization and increasing following hyperpolarization. The membrane current underlying the lEPSP (lEPSC) displayed a similar voltage dependence. 6. At stimulus intensities that led to the activation of inhibitory postsynaptic potentials (IPSPs), the lEPSP was no longer observed.(ABSTRACT TRUNCATED AT 400 WORDS)