Two opposing roles of 4-AP-sensitive K+ current in initiation and invasion of spikes in rat mesencephalic trigeminal neurons
Two opposing roles of 4-AP-sensitive K+ current in initiation and invasion of spikes in rat mesencephalic trigeminal neurons
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DOI：
10.1152/jn.00176.2006
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发表时间：
2006-10-01
影响因子：
2.5
通讯作者：
Kang, Youngnam
中科院分区：
文献类型：
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作者：
Saito, Mitsuru;Murai, Yoshinaka;Kang, Youngnam
轴突起始段在轴突棘突的起始和轴突棘突侵入索马体中起重要作用。在初级感觉神经元中，三叉神经中脑核（MTN）内的神经元对突触输入的反应具有独特的索马峰（S-spikes），因此表现出两种S-spikes，一种是由感觉感受器的轴突峰侵入引起的，另一种是由躯体输入引起的。我们研究了尖峰在MTN神经元中的起始位置，以及两种S-尖峰之间是否存在任何差异。同时膜片钳记录从索马和轴突丘揭示了一个尖峰反向传播从尖峰起始点在干轴突的索马响应于1-ms的体细胞电流脉冲，这揭示了延迟出现的S-尖峰后，电流脉冲偏移。这些启动的S-峰的幅度小于刺激干轴突产生的S-峰;然而，4-AP（
The axon initial segment plays important roles in spike initiation and invasion of axonal spikes into the soma. Among primary sensory neurons, those in the mesencephalic trigeminal nucleus (MTN) are exceptional in their ability to initiate soma spikes (S-spikes) in response to synaptic inputs, consequently displaying two kinds of S-spikes, one caused by invasion of an axonal spike arising from the sensory receptor and the other initiated by somatic inputs. We investigated where spikes are initiated in such MTN neurons and whether there are any differences between the two kinds of S-spikes. Simultaneous patch-clamp recordings from the soma and axon hillock revealed a spike-backpropagation from the spike-initiation site in the stem axon to the soma in response to 1-ms somatic current pulse, which disclosed the delayed emergence of S-spikes after the current-pulse offset. These initiated S-spikes were smaller in amplitude than S-spikes generated by stimulation of the stem axon; however, 4-AP (