論文

査読有り
2014年11月

Differential contribution of Kv4-containing channels to A-type, voltage-gated potassium currents in somatic and visceral dorsal root ganglion neurons

JOURNAL OF NEUROPHYSIOLOGY
  • Takakazu Yunoki
  • ,
  • Koichi Takimoto
  • ,
  • Kaori Kita
  • ,
  • Yasuhito Funahashi
  • ,
  • Ryosuke Takahashi
  • ,
  • Hiroko Matsuyoshi
  • ,
  • Seiji Naito
  • ,
  • Naoki Yoshimura

112
10
開始ページ
2492
終了ページ
2504
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1152/jn.00054.2014
出版者・発行元
AMER PHYSIOLOGICAL SOC

Little is known about electrophysiological differences of A-type transient K+ (K-A) currents in nociceptive afferent neurons that innervate somatic and visceral tissues. Staining with isolectin B4 (IB4)-FITC classifies L6-S1 dorsal root ganglion (DRG) neurons into three populations with distinct staining intensities: negative to weak, moderate, and intense fluorescence signals. All IB4 intensely stained cells are negative for a fluorescent dye, Fast Blue (FB), injected into the bladder wall, whereas a fraction of somatic neurons labeled by FB, injected to the external urethral dermis, is intensely stained with IB4. In whole-cell, patch-clamp recordings, phrixotoxin 2 (PaTx2), a voltage-gated K+ (Kv)4 channel blocker, exhibits voltage-independent inhibition of the K-A current in IB4 intensely stained cells but not the one in bladder-innervating cells. The toxin also shows voltage-independent inhibition of heterologously expressed Kv4.1 current, whereas its inhibition of Kv4.2 and Kv4.3 currents is voltage dependent. The swapping of four amino acids at the carboxyl portion of the S3 region between Kv4.1 and Kv4.2 transfers this characteristic. RT-PCRs detected Kv4.1 and the long isoform of Kv4.3 mRNAs without significant Kv4.2 mRNA in L6-S1 DRGs. Kv4.1 and Kv4.3 mRNA levels were higher in laser-captured, IB4-stained neurons than in bladder afferent neurons. These results indicate that PaTx2 acts differently on channels in the Kv4 family and that Kv4.1 and possibly Kv4.3 subunits functionally participate in the formation of K-A channels in a subpopulation of somatic C-fiber neurons but not in visceral C-fiber neurons innervating the bladder.

リンク情報
DOI
https://doi.org/10.1152/jn.00054.2014
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000345251800013&DestApp=WOS_CPL
ID情報
  • DOI : 10.1152/jn.00054.2014
  • ISSN : 0022-3077
  • eISSN : 1522-1598
  • Web of Science ID : WOS:000345251800013

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