HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Buy All Versions of this Article: 101/3/1407    most recent 91053.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal 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 Google Scholar Google Scholar Articles by Hsiao, C.-F. Articles by Chandler, S. H. Search for Related Content PubMed PubMed Citation Articles by Hsiao, C.-F. Articles by Chandler, S. H.

Participation of Kv1 Channels in Control of Membrane Excitability and Burst Generation in Mesencephalic V Neurons

Department of Physiological Science, University of California at Los Angeles, Los Angeles, California

Submitted 19 September 2008; accepted in final form 5 January 2009

Abstract

The function and biophysical properties of low threshold Kv1 current in control of membrane resonance, subthreshold oscillations, and bursting in mesencephalic V neurons (Mes V) were examined in rat brain stem slices (P8–P12) using whole cell current and voltage patch-clamp methods. -dendrotoxin application, a toxin with high specificity for Kv1.1, 1.2, and 1.6 channels, showed the presence of a low-threshold K⁺ current that activated rapidly around –50 mV and was relatively noninactivating over a 1-s period and had a V_1/2max of –36.2 mV. Other toxins, specific for individual channels containing either Kv 1.1, 1.2, or 1.3 -subunits, were applied individually, or in combination, and showed that Kv1 channels are heteromeric, composed of combinations of subunits. In current-clamp mode, toxin application transformed the high-frequency resonant properties of the membrane into a low-pass filter and concomitantly reduced the frequency of the subthreshold membrane oscillations. During this period, rhythmical bursting was transformed into low-frequency tonic discharge. Interestingly, in a subset of neurons that did not show bursting, low doses of -dendrotoxin (-DTX) sufficient to block 50% of the low threshold Kv1 channels induced bursting and increased the resonant peak impedance and subthreshold oscillations, which was replicated with computer simulation. This suggests that a critical balance between inward and outward currents is necessary for bursting. This was replicated with computer simulation. Single cell RT-PCR and immunohistochemical methods confirmed the presence of Kv1.1, 1.2, and 1.6 -subunits in Mes V neurons. These data indicate that low threshold Kv1 channels are responsible for membrane resonance, contribute to subthreshold oscillations, and are critical for burst generation.

This article has been cited by other articles:

				S. Ryglewski and C. Duch Shaker and Shal Mediate Transient Calcium-Independent Potassium Current in a Drosophila Flight Motoneuron J Neurophysiol, December 1, 2009; 102(6): 3673 - 3688. [Abstract] [Full Text] [PDF]