Continuous Modulation of Action Potential Firing by a Unitary GABAergic Connection in the Globus Pallidus In Vitro
Continuous Modulation of Action Potential Firing by a Unitary GABAergic Connection in the Globus Pallidus In Vitro
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DOI：
10.1523/jneurosci.1970-13.2013
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发表时间：
2013-07-31
影响因子：
5.3
通讯作者：
Korngreen, Alon
中科院分区：
文献类型：
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作者：
Bugaysen, Jenia;Bar-Gad, Izhar;Korngreen, Alon
白球（GP）神经元的放电模式受纹状体传入和局部轴突侧枝两个主要gaba能抑制来源的影响。局部gaba能GP-GP突触表现为短期抑制（STD）和非常稀疏的连通性。在GP中典型的高突触前放电率下，人们会期望这个STD是完整的，实际上消除了突触的突触后影响。为了研究突触不影响其突触后神经元的明显悖论，我们在大鼠急性脑切片中进行了双全细胞记录，并首次记录了GP-GP gaba能连接的单一ipsp。我们发现，在高突触前放电速率下，统一连接通过大氯离子驱动力、统一IPSP求和和不完全突触抑制的组合，持续调节突触后放电速率。我们的研究结果表明，尽管存在大量的STD和稀疏的连通性，GP中的局部gaba能轴突侧枝可能会响应突触后靶点突触前放电频率的变化。
The firing patterns of neurons in the globus pallidus (GP) are affected by two major sources of GABAergic inhibition: striatal afferents and local axon collaterals. Local GABAergic GP-GP synapses display short-term depression (STD) and very sparse connectivity. At the high presynaptic firing rates typical in the GP, one would expect this STD to be complete, practically canceling the postsynaptic impact of the synapse. To investigate the apparent paradox of a synapse not affecting its postsynaptic neuron, we performed dual whole-cell recordings in acute brain slices from rats and recorded, for the first time, unitary IPSPs from a GP-GP GABAergic connection. We show that at high presynaptic firing rates the unitary connection continuously modulates the postsynaptic firing rate through a combination of large chloride driving force, unitary IPSP summation, and incomplete synaptic depression. Our findings indicate that, despite substantial STD and sparse connectivity, local GABAergic axon collaterals in the GP may echo the changes in presynaptic firing frequency across postsynaptic targets.