Distinct local circuits between neocortical pyramidal cells and fast-spiking interneurons in young adult rats
Distinct local circuits between neocortical pyramidal cells and fast-spiking interneurons in young adult rats
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DOI：
10.1152/jn.00750.2002
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发表时间：
2003-02-01
影响因子：
2.5
通讯作者：
Audinat, E
中科院分区：
文献类型：
--
作者：
Angulo, MC;Staiger, JF;Audinat, E
在28- 52日龄大鼠急性皮层脑片上，采用配对记录结合形态学分析的方法，研究了第V层锥体细胞与GABA能快速发放中间神经元（GABA能FS）之间的联系。以0.2Hz的刺激频率在锥体细胞中引起的成对尖峰在FS中间神经元中诱导单一兴奋性突触后电流（EPSC），其显示易化（48%）、抑制（38.5%）或既不抑制也不易化（13.5%）。对EPSC振幅分布的分析表明，抑郁性连接总是表现出多个功能性释放部位。相反，促进连接由一个或多个释放位点组成。在-72 mV的保持电位下，促进与单个释放位点连接的量子尺寸（q）和释放概率（p）分别为-21.9 +/- 7.5 pA和0.49 +/- 0.19（SD）。通过降低释放概率获得了平均q和显示多个位点的连接处的估计释放位点数（n），并且在抑制和促进突触之间没有差异（抑制连接：q = -15.3 +/- 2.5 pA，n = 5.1 +/- 3，促进连接：q = -23.9 +/- 9.8 pA，n = 7.8 +/- 5.4）。然而，促进多位点突触的量子含量（1.9 +/- 1.5）与抑制连接的量子含量（4.1 +/- 3.9）显著不同。最后，定量形态学分析表明，大多数的锥体细胞显示促进可以区分从那些显示抑郁症由一个更密集的分支顶端树突树。因此，两种类型的形态不同的锥体细胞形成兴奋性连接FS中间神经元，不同的短期可塑性特征。促进和压抑的连接可能提供了一个不同的控制FS细胞的时间信息处理，从而精细地调节这些interneurons在新皮层网络的年轻成年大鼠的抑制作用。
Connections between layer V pyramidal cells and GABAergic fast-spiking interneurons (pyramidal-FS) were studied by paired recordings combined with morphological analyses in acute neocortical slices from 28- to 52-day-old rats. Pairs of spikes elicited in pyramidal cells at a stimulation rate of 0.2 Hz induced unitary excitatory postsynaptic currents (EPSCs) in FS interneurons that displayed facilitation (48%), depression (38.5%), or neither depression nor facilitation (13.5%). Analyses of the EPSC amplitude distributions indicate that depressing connections always showed multiple functional release sites. On the contrary, facilitating connections consisted either of one or several release sites. At a holding potential of -72 mV, the quantal size (q) and the release probability (p) of facilitating connections with a single release site were -21.9 +/- 7.5 pA and 0.49 +/- 0.19 (SD), respectively. The mean q and the estimated number of release sites (n) at connections showing multiple sites were obtained by decreasing the release probability and did not differ between depressing and facilitating synapses (depressing connections: q = -15.3 +/- 2.5 pA, n = 5.1 +/- 3, facilitating connections: q = -23.9 +/- 9.8 pA, n = 7.8 +/- 5.4). However, the quantal content at facilitating synapses with multiple sites (1.9 +/- 1.5) was significantly different from that at depressing connections (4.1 +/- 3.9). Finally, quantitative morphological analyses revealed that most of the pyramidal cells displaying facilitation can be differentiated from those displaying depression by a more densely branched apical dendritic tree. Therefore two types of morphologically distinct pyramidal cells form excitatory connections with FS interneurons that differ in their short-term plasticity characteristics. Facilitating and depressing connections may provide a differential control of the temporal information processing of FS cells and thus finely regulate the inhibitory effect of these interneurons in neocortical networks of young adult rats.