QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

This Article Full Text Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (17) Citing Articles via Google Scholar Google Scholar Articles by Malin, S. A. Articles by Nerbonne, J. M. Search for Related Content PubMed PubMed Citation Articles by Malin, S. A. Articles by Nerbonne, J. M.

 Previous Article  |  Next Article 

The Journal of Neuroscience, October 15, 2001, 21(20):8004-8014

Molecular Heterogeneity of the Voltage-Gated Fast Transient Outward K⁺ Current, I_Af, in Mammalian Neurons

Sacha A. Malin and Jeanne M. Nerbonne

Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110

Recently, we identified four kinetically distinct voltage-gated K⁺ currents, I_Af, I_As, I_K, and I_SS, in rat superior cervical ganglion (SCG) neurons and demonstrated that I_Af and I_As are differentially expressed in type I (I_Af, I_K, I_SS), type II (I_Af, I_As, I_K, I_SS), and type III (I_K, I_SS) SCG cells. In addition, we reported that I_Af is eliminated in most (~70%) SCG cells expressing Kv4.2W362F, a Kv4 subfamily-specific dominant negative. The molecular correlate(s) of the residual I_Af, as well as that of I_As, I_K, and I_SS, however, are unknown. The experiments here were undertaken to explore the role of Kv1 -subunits in the generation of voltage-gated K⁺ currents in SCG neurons. Using the Biolistics Gene Gun, cDNA constructs encoding a Kv1 subfamily-specific dominant negative, Kv1.5W461F, and enhanced green fluorescent protein (EGFP) were introduced into SCG neurons. Whole-cell recordings from EGFP-positive Kv1.5W461F-expressing cells revealed a selective decrease in the percentage of type I cells and an increase in type III cells, indicating that I_Af is gated by Kv1 -subunits in a subset of type I SCG neurons. I_Af is eliminated in all SCG cells expressing both Kv1.5W461F and Kv4.2W362F. I_{Af decay} values in Kv1.5W461F-expressing and Kv4.2W362F-expressing type I cells are significantly different, revealing that Kv1 and Kv4 -subunits encode kinetically distinct I_Af channels. Expression of Kv1.5W461F increases excitability by decreasing action potential current thresholds and converts phasic cells to adapting or tonic firing. Interestingly, the molecular heterogeneity of I_Af channels has functional significance because Kv1- and Kv4-encoded I_Af play distinct roles in the regulation of neuronal excitability.

Key words: K⁺ channels; I_A; Kv1 -subunits; Kv4 -subunits; Kv1.5W461F; transgenics; gene gun; neuronal excitability; repetitive firing patterns

---

Copyright © 2001 Society for Neuroscience  0270-6474/01/21208004-11$05.00/0

This article has been cited by other articles:

				M. A. Doczi, A. D. Morielli, and D. H. Damon Kv1.3 channels in postganglionic sympathetic neurons: expression, function, and modulation Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2008; 295(3): R733 - R740. [Abstract] [Full Text] [PDF]

				O. Colinas, F. D. Perez-Carretero, J. R. Lopez-Lopez, and M. T. Perez-Garcia A Role for DPPX Modulating External TEA Sensitivity of Kv4 Channels J. Gen. Physiol., April 28, 2008; 131(5): 455 - 471. [Abstract] [Full Text] [PDF]

				X. Ma, K. Bielefeldt, Z. Y. Tan, C. A. Whiteis, V. Snitsarev, F. M. Abboud, and M. W. Chapleau Dual mechanisms of angiotensin-induced activation of mouse sympathetic neurones J. Physiol., May 15, 2006; 573(1): 45 - 63. [Abstract] [Full Text] [PDF]

				J. Kim, D.-S. Wei, and D. A. Hoffman Kv4 potassium channel subunits control action potential repolarization and frequency-dependent broadening in rat hippocampal CA1 pyramidal neurones J. Physiol., November 15, 2005; 569(1): 41 - 57. [Abstract] [Full Text] [PDF]

				L. A. Kim, J. Furst, M. H. Butler, S. Xu, N. Grigorieff, and S. A. N. Goldstein Ito Channels Are Octomeric Complexes with Four Subunits of Each Kv4.2 and K+ Channel-interacting Protein 2 J. Biol. Chem., February 13, 2004; 279(7): 5549 - 5554. [Abstract] [Full Text] [PDF]

				R. Shibata, H. Misonou, C. R. Campomanes, A. E. Anderson, L. A. Schrader, L. C. Doliveira, K. I. Carroll, J. D. Sweatt, K. J. Rhodes, and J. S. Trimmer A Fundamental Role for KChIPs in Determining the Molecular Properties and Trafficking of Kv4.2 Potassium Channels J. Biol. Chem., September 19, 2003; 278(38): 36445 - 36454. [Abstract] [Full Text] [PDF]

				S. A. Malin and J. M. Nerbonne Delayed Rectifier K+ Currents, IK, Are Encoded by Kv2 alpha -Subunits and Regulate Tonic Firing in Mammalian Sympathetic Neurons J. Neurosci., December 1, 2002; 22(23): 10094 - 10105. [Abstract] [Full Text] [PDF]

				J. Mitterdorfer and B. P. Bean Potassium Currents during the Action Potential of Hippocampal CA3 Neurons J. Neurosci., December 1, 2002; 22(23): 10106 - 10115. [Abstract] [Full Text] [PDF]

				T. W. Bailey, Y.-H. Jin, M. W. Doyle, and M. C. Andresen Vanilloid-Sensitive Afferents Activate Neurons with Prominent A-Type Potassium Currents in Nucleus Tractus Solitarius J. Neurosci., September 15, 2002; 22(18): 8230 - 8237. [Abstract] [Full Text] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help