Physiological role of calcium-activated potassium currents in the rat lateral amygdala

Faber, ESL and Sah, P (2002) Physiological role of calcium-activated potassium currents in the rat lateral amygdala. Journal of Neuroscience, 22 5: 1618-1628.

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Author Faber, ESL
Sah, P
Title Physiological role of calcium-activated potassium currents in the rat lateral amygdala
Journal name Journal of Neuroscience   Check publisher's open access policy
ISSN 0270-6474
Publication date 2002-01-01
Year available 2002
Sub-type Article (original research)
Open Access Status File (Publisher version)
Volume 22
Issue 5
Start page 1618
End page 1628
Total pages 11
Place of publication Washington
Publisher Soc Neuroscience
Language eng
Abstract Principal neurons in the lateral nucleus of the amygdala (LA) exhibit a continuum of firing properties in response to prolonged current injections ranging from those that accommodate fully to those that fire repetitively. In most cells, trains of action potentials are followed by a slow after hyperpolarization (AHP) lasting several seconds. Reducing calcium influx either by lowering concentrations of extracellular calcium or by applying nickel abolished the AHP, confirming it is mediated by calcium influx. Blockade of large conductance calcium-activated potassium channel (BK) channels with paxilline, iberiotoxin, or TEA revealed that BK channels are involved in action potential repolarization but only make a small contribution to the fast AHP that follows action potentials. The fast AHP was, however, markedly reduced by low concentrations of 4-aminopyridine and alpha-dendrotoxin, indicating the involvement of voltage-gated potassium channels in the fast AHP. The medium AHP was blocked by apamin and UCL1848, indicating it was mediated by small conductance calcium-activated potassium channel (SK) channels. Blockade of these channels had no effect on instantaneous firing. However, enhancement of the SK-mediated current by 1-ethyl-2-benzimidazolinone or paxilline increased the early interspike interval, showing that under physiological conditions activation of SK channels is insufficient to control firing frequency. The slow AHP, mediated by non-SK BK channels, was apamin-insensitive but was modulated by carbachol and noradrenaline. Tetanic stimulation of cholinergic afferents to the LA depressed the slow AHP and led to an increase in firing. These results show that BK, SK, and non-BK SK-mediated calcium-activated potassium currents are present in principal LA neurons and play distinct physiological roles.
Keyword Neurosciences
Bk Channels
Sk Channels
Hippocampal Pyramidal Cells
Ca2+-activated K+ Channel
Action-potential Repolarization
Adrenal Chromaffin Cells
Recorded Invitro
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
Queensland Brain Institute Publications
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Citation counts: TR Web of Science Citation Count  Cited 161 times in Thomson Reuters Web of Science Article | Citations
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Created: Mon, 13 Aug 2007, 22:51:01 EST