Roles of specific Kv channel types in repolarization of the action potential in genetically identified subclasses of pyramidal neurons in mouse neocortex.
Roles of specific Kv channel types in repolarization of the action potential in genetically identified subclasses of pyramidal neurons in mouse neocortex.
复制标题
DOI：
10.1152/jn.01028.2015
复制
发表时间：
2016-05
影响因子：
2.5
通讯作者：
D. Pathak;D. Guan;R. Foehring
中科院分区：
文献类型：
--
作者：
D. Pathak;D. Guan;R. Foehring
动作电位（AP）是可兴奋细胞的基本特征，是神经系统中长距离信号传递的基础。在不同的神经元类型中，AP的外观和潜在的复极化机制存在相当大的差异（在Bean BP中综述）。Nat Rev Neurosci 8：451-465，2007），包括锥体细胞亚型。在目前的工作中，我们使用特定的药理学阻断剂测试的贡献Kv 1，Kv 2，或Kv 4通道的复极化的单个AP在两个遗传定义的亚群的锥体细胞在第5层的小鼠体感皮层（etv 1和GLT），以及锥体细胞从层2/3。这三种亚型在AP性质上不同（Groh A，Meyer HS，施密特EF，Heintz N，Sakmann B，Krieger P. CereB Cortex 20：826-836，2010; Guan D，Armstrong WE，Foehring RC. J Neurophysiol 113：2014-2032，2015）以及椎板位置、形态和投影目标。我们询问Kv 1、Kv 2和Kv 4通道在AP复极化中的作用以及潜在机制是否依赖于锥体细胞亚型。我们发现，Kv 4通道是至关重要的参与复极化新皮质锥体细胞。Kv 1通道的作用也存在锥体细胞亚型特异性差异。只有Kv 4通道参与glt细胞窄AP的复极化。相比之下，在etv 1小区和第2/3层小区中，除了Kv 4信道之外，更广泛的AP还被Kv 1信道部分重新极化。与其在阈下范围内的激活一致，Kv 1通道也调节所有锥体细胞亚型的AP电压阈值。
The action potential (AP) is a fundamental feature of excitable cells that serves as the basis for long-distance signaling in the nervous system. There is considerable diversity in the appearance of APs and the underlying repolarization mechanisms in different neuronal types (reviewed in Bean BP. Nat Rev Neurosci 8: 451-465, 2007), including among pyramidal cell subtypes. In the present work, we used specific pharmacological blockers to test for contributions of Kv1, Kv2, or Kv4 channels to repolarization of single APs in two genetically defined subpopulations of pyramidal cells in layer 5 of mouse somatosensory cortex (etv1 and glt) as well as pyramidal cells from layer 2/3. These three subtypes differ in AP properties (Groh A, Meyer HS, Schmidt EF, Heintz N, Sakmann B, Krieger P. Cereb Cortex 20: 826-836, 2010; Guan D, Armstrong WE, Foehring RC. J Neurophysiol 113: 2014-2032, 2015) as well as laminar position, morphology, and projection targets. We asked what the roles of Kv1, Kv2, and Kv4 channels are in AP repolarization and whether the underlying mechanisms are pyramidal cell subtype dependent. We found that Kv4 channels are critically involved in repolarizing neocortical pyramidal cells. There are also pyramidal cell subtype-specific differences in the role for Kv1 channels. Only Kv4 channels were involved in repolarizing the narrow APs of glt cells. In contrast, in etv1 cells and layer 2/3 cells, the broader APs are partially repolarized by Kv1 channels in addition to Kv4 channels. Consistent with their activation in the subthreshold range, Kv1 channels also regulate AP voltage threshold in all pyramidal cell subtypes.