Excitatory actions of GABA in the cortex
Excitatory actions of GABA in the cortex
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DOI：
10.1016/s0896-6273(02)01146-7
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发表时间：
2003-01-23
期刊：
影响因子：
16.2
通讯作者：
Stuart, GJ
中科院分区：
文献类型：
--
作者：
Gulledge, AT;Stuart, GJ
在维持细胞内阴离子生理浓度的条件下，GABA能输入如何与兴奋性输入相互作用，我们知之甚少。利用细胞外和Granicidin穿孔贴片记录，我们发现在成熟的皮质锥体神经元中，体细胞和树突的GABA反应是去极化的，当与近端兴奋性输入相结合时，可以促进动作电位的产生。树突状GABA的反应是兴奋的，而体细胞的GABA反应在与兴奋性输入一致时是抑制的，但在较早的时间是兴奋的。GABA的这些兴奋作用即使在GABA逆转电位低于动作电位阈值并且在体树突轴上基本一致的情况下也会发生，并且当GABA能输入在时间或空间上与同时兴奋隔离时也会出现。我们的发现表明，在某些情况下，GABA将在大脑皮层突触整合中发挥兴奋作用。
Little is known about how GABAergic inputs interact with excitatory inputs under conditions that maintain physiological concentrations of intracellular anions. Using extracellular and gramicidin perforated-patch recording, we show that somatic and dendritic GABA responses in mature cortical pyramidal neurons are depolarizing from rest and can facilitate action potential generation when combined with proximal excitatory input. Dendritic GABA responses were excitatory regardless of timing, whereas somatic GABA responses were inhibitory when coincident with excitatory input but excitatory at earlier times. These excitatory actions of GABA occur even though the GABA reversal potential is below action potential threshold and largely uniform across the somato-dendritic axis, and arise when GABAergic inputs are temporally or spatially isolated from concurrent excitation. Our findings demonstrate that under certain circumstances GABA will have an excitatory role in synaptic integration in the cortex.