Comparison of IPSCs evoked by spiny and fast-spiking neurons in the neostriatum
Comparison of IPSCs evoked by spiny and fast-spiking neurons in the neostriatum
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DOI：
10.1523/jneurosci.2163-04.2004
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发表时间：
2004-09-08
影响因子：
5.3
通讯作者：
Wilson, CJ
中科院分区：
文献类型：
--
作者：
Koos, T;Tepper, JM;Wilson, CJ
新纹状体的大多数神经元是GABA能的棘状投射神经元，具有广泛的局部轴突侧支，主要支配其他棘状投射神经元。刺状神经元的GABA能输入的另一个来源来自少量的中间神经元，其中最具特征的是含有小清蛋白的快速尖峰中间神经元。直到最近才证实棘状神经元侧支抑制，因为在索马记录的IPSPs非常小。相比之下，神经元间抑制很容易检测到，包括更大的IPSP。在这里，我们报告的应用量子分析和房室模型比较和对比IPSC的棘状神经元起源于轴突侧支和中间神经元。结果表明，在棘状和神经元间突触的个人释放网站有类似的量子大小和基线释放概率。神经元间的单一IPSC是几倍大，因为它们在神经元上的近端位置，因为它们具有大量的递质释放位点。尽管它们能向索马传递的电流量很小，但棘细胞侧支突触具有中等高的基线释放概率（0.5 - 0.9），这表明它们并不是因为某种形式的抑制或调节而变弱。单一侧支突触电流的大小在发育过程中单调增加。这些结果反对模型的竞争性抑制在新纹状体，包括那些竞争性抑制是短暂有效的发展和学习过程中，并提出了不同的作用，多刺细胞轴突侧支。
Most neurons in the neostriatum are GABAergic spiny projection neurons with extensive local axon collaterals innervating principally other spiny projection neurons. The other source of GABAergic inputs to spiny neurons derives from a small number of interneurons, of which the best characterized are the parvalbumin-containing, fast-spiking interneurons. Spiny neuron collateral inhibition was not demonstrated until recently, because the IPSPs recorded at the soma are surprisingly small. In contrast, interneuronal inhibition was readily detected, comprising much larger IPSPs. Here, we report the application of quantal analysis and compartmental modeling to compare and contrast IPSCs in spiny neurons originating from axon collaterals and interneurons. The results indicate that individual release sites at spiny and interneuron synapses have similar quantal sizes and baseline release probabilities. Interneuronal unitary IPSCs are several times larger because of their proximal location on the neuron and because they have a larger number of transmitter release sites. Despite the small amount of current they can deliver to the soma, spiny cell collateral synapses had moderately high baseline release probabilities (0.5 - 0.9), suggesting that they are not weak because of some form of depression or modulation. The size of unitary collateral synaptic currents increased monotonically during development. These results argue against models of competitive inhibition in neostriatum, including those in which competitive inhibition is transiently effective during development and learning, and suggest a different role for the spiny cell axon collaterals.