...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Neurophysiology >Two opposing roles of 4-AP-sensitive K+ current in initiation and invasion of spikes in rat mesencephalic trigeminal neurons.
【24h】

Two opposing roles of 4-AP-sensitive K+ current in initiation and invasion of spikes in rat mesencephalic trigeminal neurons.

机译：4-AP敏感K +电流在大鼠中脑三叉神经元尖峰的起始和侵袭中的两个相反的作用。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

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 (< or =0.5 mM) eliminated the amplitude difference. Furthermore, 4-AP dramatically shortened the delay in spike initiation without affecting the spike-backpropagation time in the stem axon, whereas it substantially prolonged the refractory period of S-spikes arising from axonal-spike invasion without significantly affecting that of presumed axonal spikes. These observations suggest that 4-AP-sensitive K(+) currents exert two opposing effects on S-spikes depending on their origins: suppression of spike initiation and facilitation of axonal-spike invasion at higher frequencies. Consistent with these findings, strong immunoreactivities for Kv1.1 and Kv1.6, among 4-AP-sensitive and low-voltage-activated Kv1 family examined, were detected in the soma but not in the stem axon of MTN neurons.
机译：轴突初始节在突突的产生和突突突突侵入体中起重要作用。在主要的感觉神经元中，中脑三叉神经核（MTN）中的神经元在突触输入引起的体细胞尖峰（S-spikes）引发能力方面异常出色，因此显示出两种S-spikes，一种是由于轴突的侵袭引起的。由感觉感受器引起的尖峰，另一个由体细胞输入引发。我们调查了在此类MTN神经元中从哪里引发尖峰，以及两种S尖峰之间是否存在差异。体细胞和轴突岗的同时膜片钳记录显示，响应于1毫秒的体细胞电流脉冲，从茎轴突中的突突起始位点向体细胞的突突反向传播，这揭示了在S突突后S突突的出现延迟。电流脉冲偏移。这些起始的S峰的幅度小于通过刺激茎轴突产生的S峰。但是，4-AP（<或= 0.5 mM）消除了幅度差异。此外，4-AP显​​着缩短了穗突起始的延迟，而又不影响茎轴突中穗反向传播的时间，而它显着延长了由轴突穗侵袭引起的S穗的不应期，而不会显着影响假定的轴突穗。这些观察结果表明，对4-AP敏感的K（+）电流根据S-spike的起源对其产生两个相反的影响：抑制尖峰的产生和促进轴突尖峰在较高频率下的入侵。与这些发现一致，在被检查的4-AP敏感和低电压激活的Kv1家族中，对MTv神经元的茎轴突中未检测到针对Kv1.1和Kv1.6的强免疫反应性。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号