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Title: Properties and physiological function of Ca 2+ -dependent K + currents in uniglomerular olfactory projection neurons
Authors: Bradler, C
Warren, B
Bardos, V
Schleicher, S
Klein, A
Kloppenburg, P
First Published: 10-May-2016
Publisher: American Physiological Society
Citation: Journal of Neurophysiology, 2016, 115 (5), pp. 2330-2340
Abstract: Ca2+-activated potassium currents [IK(Ca)] are an important link between the intracellular signaling system and the membrane potential, which shapes intrinsic electrophysiological properties. To better understand the ionic mechanisms that mediate intrinsic firing properties of olfactory uniglomerular projection neurons (uPNs), we used whole cell patch-clamp recordings in an intact adult brain preparation of the male cockroach Periplaneta americana to analyze IK(Ca). In the insect brain, uPNs form the principal pathway from the antennal lobe to the protocerebrum, where centers for multimodal sensory processing and learning are located. In uPNs the activation of IK(Ca) was clearly voltage and Ca2+ dependent. Thus under physiological conditions IK(Ca) is strongly dependent on Ca2+ influx kinetics and on the membrane potential. The biophysical characterization suggests that IK(Ca) is generated by big-conductance (BK) channels. A small-conductance (SK) channel-generated current could not be detected. IK(Ca) was sensitive to charybdotoxin (CTX) and iberiotoxin (IbTX) but not to apamin. The functional role of IK(Ca) was analyzed in occlusion experiments under current clamp, in which portions of IK(Ca) were blocked by CTX or IbTX. Blockade of IK(Ca) showed that IK(Ca) contributes significantly to intrinsic electrophysiological properties such as the action potential waveform and membrane excitability.
DOI Link: 10.1152/jn.00840.2015
ISSN: 0022-3077
eISSN: 1522-1598
Version: Post-print
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2016, American Physiological Society. Deposited with reference to the publisher’s open access archiving policy. (
Appears in Collections:Published Articles, Dept. of Neuroscience, Psychology and Behaviour

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