Slow GABA(A) mediated synaptic transmission in rat visual cortex.
Slow GABA(A) mediated synaptic transmission in rat visual cortex.
复制标题
慢速GABA（A）大鼠视觉皮层中介导的突触传播。
DOI：
10.1186/1471-2202-9-8
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发表时间：
2008-01-16
期刊：
影响因子：
2.4
通讯作者：
MacIver, M. Bruce
中科院分区：
文献类型：
--
作者：
Sceniak, Michael P.;MacIver, M. Bruce
先前关于新皮层抑制的报道表明，抑制主要通过表现出快速动力学的GABAA受体介导。在海马体内，已经表明GABAA反应可以采取快速或缓慢反应动力学的形式。我们的研究结果表明，第一次，新皮层显示缓慢的GABAA受体介导的抑制性突触后电流（IPSC）的突触反应。这些IPSC在动力学和神经学上与海马中发现的反应相似，尽管诱发反应的解剖学特异性是海马所独有的。在大鼠视皮层锥体神经元和抑制性神经元中记录到自发慢GABAA IPSC。GABAA慢IPSC的上升时间和衰减时间常数，但幅度方面的快速反应显着不同。自发发生的GABAA慢IPSC的频率比快sIPSC低近100倍，并且两者都被氯离子通道阻断剂印防己毒素完全消除。GABAA亚基特异性拮抗剂呋塞米抑制自发性和诱发性GABAA快速IPSC，但不抑制GABAA介导的慢速IPSC。使用最小刺激的解剖特异性是明显的：具有缓慢动力学的IPSC主要通过刺激第4层锥体神经元的第1/2层顶端树突区及其基底树突来诱发，而GABAA快速IPSC通过刺激整个树突分支来诱发。许多诱发的IPSC也由快和慢IPSC成分的组合组成。GABAA慢IPSC显示的持续时间比典型的GABAA快IPSC长约4倍，但比GABAB介导的抑制短。诱发慢IPSC的解剖学和药理学特异性表明突触输入的独特起源。将GABAA慢IPSC转化为皮质功能的计算模型将有助于提高我们对皮质信息处理的理解。
Previous reports of inhibition in the neocortex suggest that inhibition is mediated predominantly through GABAA receptors exhibiting fast kinetics. Within the hippocampus, it has been shown that GABAA responses can take the form of either fast or slow response kinetics. Our findings indicate, for the first time, that the neocortex displays synaptic responses with slow GABAA receptor mediated inhibitory postsynaptic currents (IPSCs). These IPSCs are kinetically and pharmacologically similar to responses found in the hippocampus, although the anatomical specificity of evoked responses is unique from hippocampus. Spontaneous slow GABAA IPSCs were recorded from both pyramidal and inhibitory neurons in rat visual cortex. GABAA slow IPSCs were significantly different from fast responses with respect to rise times and decay time constants, but not amplitudes. Spontaneously occurring GABAA slow IPSCs were nearly 100 times less frequent than fast sIPSCs and both were completely abolished by the chloride channel blocker, picrotoxin. The GABAA subunit-specific antagonist, furosemide, depressed spontaneous and evoked GABAA fast IPSCs, but not slow GABAA-mediated IPSCs. Anatomical specificity was evident using minimal stimulation: IPSCs with slow kinetics were evoked predominantly through stimulation of layer 1/2 apical dendritic zones of layer 4 pyramidal neurons and across their basal dendrites, while GABAA fast IPSCs were evoked through stimulation throughout the dendritic arborization. Many evoked IPSCs were also composed of a combination of fast and slow IPSC components. GABAA slow IPSCs displayed durations that were approximately 4 fold longer than typical GABAA fast IPSCs, but shorter than GABAB-mediated inhibition. The anatomical and pharmacological specificity of evoked slow IPSCs suggests a unique origin of synaptic input. Incorporating GABAA slow IPSCs into computational models of cortical function will help improve our understanding of cortical information processing.
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影响因子：
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作者：
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