title: Properties and physiological function of Ca2+-dependent K+ currents in uniglomerular olfactory projection neurons.
abstract: Ca(2+)-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 Ca(2+) dependent. Thus under physiological conditions IK(Ca) is strongly dependent on Ca(2+) 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.
authors.affiliation: Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
authors.forename: Cathleen
authors.initials: C
authors.lastname: Bradler
authors.affiliation: Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
authors.forename: Ben
authors.initials: B
authors.lastname: Warren
authors.affiliation: Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
authors.forename: Viktor
authors.initials: V
authors.lastname: Bardos
authors.affiliation: Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Schleicher
authors.affiliation: Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Klein
authors.affiliation: Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany peter.kloppenburg@uni-koeln.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Kloppenburg
mesh_terms: D000200:Action Potentials; D000818:Animals; D001030:Apamin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D018999:Charybdotoxin / Q000494:pharmacology; D003058:Cockroaches; D008297:Male; D009833:Olfactory Pathways / Q000166:cytology / Q000502:physiology*; D010455:Peptides / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D024681:Potassium Channels, Calcium-Activated / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011984:Sensory Receptor Cells / Q000378:metabolism / Q000502:physiology*
chemical_list: D010455:Peptides; D026902:Potassium Channel Blockers; D024681:Potassium Channels, Calcium-Activated; D018999:Charybdotoxin; D001030:Apamin; C064719:iberiotoxin; D002118:Calcium
keywords: Periplaneta americana; antennal lobe; chemosensory; glomerulus; olfaction
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