title: The Outwardly Rectifying Current of Layer 5 Neocortical Neurons that was Originally Identified as "Non-Specific Cationic" Is Essentially a Potassium Current.
abstract: In whole-cell patch clamp recordings from layer 5 neocortical neurons, blockade of voltage gated sodium and calcium channels leaves a cesium current that is outward rectifying. This current was originally identified as a "non-specific cationic current", and subsequently it was hypothesized that it is mediated by TRP channels. In order to test this hypothesis, we used fluorescence imaging of intracellular sodium and calcium indicators, and found no evidence to suggest that it is associated with influx of either of these ions to the cell body or dendrites. Moreover, the current is still prominent in neurons from TRPC1-/- and TRPC5-/- mice. The effects on the current of various blocking agents, and especially its sensitivity to intracellular tetraethylammonium, suggest that it is not a non-specific cationic current, but rather that it is generated by cesium-permeable delayed rectifier potassium channels.
authors.affiliation: Koret School of Veterinary Medicine, Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
authors.forename: Omer
authors.initials: O
authors.lastname: Revah
authors.affiliation: Koret School of Veterinary Medicine, Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
authors.forename: Lior
authors.initials: L
authors.lastname: Libman
authors.affiliation: Department of Physiology and Cell Biology, Faculty of Health Sciences and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel.
authors.forename: Ilya A
authors.initials: IA
authors.lastname: Fleidervish
authors.affiliation: Koret School of Veterinary Medicine, Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gutnick
mesh_terms: D000818:Animals; D002412:Cations; D002463:Cell Membrane Permeability; D015640:Ion Channel Gating; D007700:Kinetics; D018345:Mice, Knockout; D019579:Neocortex / Q000166:cytology*; D015221:Potassium Channels / Q000378:metabolism*; D017966:Pyramidal Cells / Q000166:cytology / Q000378:metabolism*; D050052:TRPC Cation Channels / Q000378:metabolism
chemical_list: D002412:Cations; D015221:Potassium Channels; D050052:TRPC Cation Channels