Manipulation of the potassium channel Kv1.1 and its effect on neuronal excitability in rat sensory neurons

Xuan Chi Xian, Grant Nicol

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Potassium channels play a critical role in regulating many aspects of action potential (AP) firing. To establish the contribution of the voltage-dependent potassium channel Kv1.1 in regulating excitability, we used the selective blocker dendrotoxin-K (DTX-K) and small interfering RNA (siRNA) targeted to Kv1.1 to determine their effects on AP firing in small-diameter capsaicin-sensitive sensory neurons. A 5-min exposure to 10 nM DTX-K suppressed the total potassium current (IK) measured at +40 mV by about 33%. DTX-K produced a twofold increase in the number of APs evoked by a ramp of depolarizing current. Associated with increased firing was a decrease in firing threshold and rheobase. DTX-K did not alter the resting membrane potential or the AP duration. A 48-h treatment with siRNA targeted to Kv1.1 reduced the expression of this channel protein by about 60% as measured in Western blots. After treatment with siRNA, IK was no longer sensitive to DTX-K, indicating a loss of functional protein. Similarly, after siRNA treatment exposure to DTX-K had no effect on the number of evoked APs, firing threshold, or rheobase. However, after siRNA treatment, the firing threshold had values similar to those obtained after acute exposure to DTX-K, suggesting that the loss of Kv1.1 plays a critical role in setting this parameter of excitability. These results demonstrate that Kv1.1 plays an important role in limiting AP firing and that siRNA may be a useful approach to establish the role of specific ion channels in the absence of selective antagonists.

Original languageEnglish
Pages (from-to)2683-2692
Number of pages10
JournalJournal of Neurophysiology
Volume98
Issue number5
DOIs
StatePublished - Nov 2007

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Kv1.1 Potassium Channel
Sensory Receptor Cells
Small Interfering RNA
Action Potentials
Architectural Accessibility
Capsaicin
Potassium Channels
dendrotoxin K
Ion Channels
Membrane Potentials
Potassium
Proteins
Western Blotting

ASJC Scopus subject areas

  • Physiology
  • Neuroscience(all)

Cite this

Manipulation of the potassium channel Kv1.1 and its effect on neuronal excitability in rat sensory neurons. / Xian, Xuan Chi; Nicol, Grant.

In: Journal of Neurophysiology, Vol. 98, No. 5, 11.2007, p. 2683-2692.

Research output: Contribution to journalArticle

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