Temporal overlap of excitatory and inhibitory afferent input in guinea-pig CA1 pyramidal cells
Temporal overlap of excitatory and inhibitory afferent input in guinea-pig CA1 pyramidal cells
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DOI：
10.1111/j.1469-7793.1999.0485v.x
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发表时间：
1999-04-15
影响因子：
5.5
通讯作者：
Stelzer, A
中科院分区：
文献类型：
--
作者：
Karnup, S;Stelzer, A
1. 在CA1锥体细胞中，研究了诱发突触兴奋和GABA(A)介导的抑制的时间相互作用。对豚鼠海马片锥体细胞树突、体细胞和中间神经元进行了单细胞和成对的细胞内记录。进行电流钳、锐电极和全细胞电压钳记录。树突和躯体抑制反应的动力学是相似的。值得注意的是，树突单一型IPSPs的动力学与体细胞单一型IPSPs的动力学一样快。GABA(A)介导的影响存在于整个正锥体细胞EPSP/EPSC。比较药理学分离的单突触IPSPs、IPSCs和抑制电导（S-GABAA）的动力学，g（GABAA）的动力学最快。单突触g（GABBA）与诱发EPSP/EPSC的上升相密切重叠。g（GABAA）的发作与EPBP/ epsc的发作同时或先于EPBP/ epsc的发作。在80%的配对记录中，前馈ipsp的开始与锥体细胞EPSP的上升相一致。最快的前馈抑制反应与诱发兴奋几乎完全重叠。复发性ipsp的发作并不发生在EPSP的上升期，而是在锥体细胞EPSP峰值后约3.0 ms发生。在同时记录的锥体细胞中，在低于诱发epsp阈值的刺激强度下，观察到正视诱发的神经元间峰。最弱的兴奋性输入激活前馈抑制反应，前馈抑制和诱发兴奋之间存在较大的时间重叠，表明CA1中存在任何兴奋性输入。是由快速突触抑制有效控制的。
1. The temporal interaction of evoked synaptic excitation and GABA(A)-mediated inhibition was examined in CA1 pyramidal cells. Single and paired intracellular recordings were carried out in pyramidal cell dendrites and somata, and interneurons of the guinea-pig hippocampal slice. Current-clamp, sharp electrode and whole-cell voltage-clamp recordings were made.2. Kinetics of dendritic and somatic inhibitory responses were similar. Notably, kinetics of dendritic unitary IPSPs were as fast as kinetics of somatic unitary IPSPs.3. GABA(A)-mediated influences were present throughout the orthodromic pyramidal cell EPSP/EPSC. Comparison of the kinetics of pharmacologically isolated monosynaptic IPSPs, IPSCs and inhibitory conductances (S-GABAA), showed fastest kinetics for g(GABAA). Close temporal overlap was observed between monosynaptic g(GABBA) and the rising phase of the evoked EPSP/EPSC. The onset of g(GABAA) coincided with or preceded onset of the EPBP/EPSC.4. Onsets of feedforward IPSPs coincided with the rising phase of the pyramidal cell EPSP in > 80% of paired recordings. Fastest feedforward inhibitory responses exerted near complete overlap with evoked excitation.5. Onsets of recurrent IPSPs did not occur during the rising phase of the evoked EPSP, but > 3.0 ms after the peak of the pyramidal cell EPSP.6. Orthodromically evoked interneuron spikes were observed at stimulation intensities that were below the threshold for eliciting EPSPs in concomitantly recorded pyramidal cells. The activation of feedforward inhibitory responses by weakest excitatory input, and the large temporal overlap between feedforward inhibition and evoked excitation, suggest that in situ any excitatory input in CA1. is effectively controlled by fast synaptic inhibition.