title: Distinct Kv channel subtypes contribute to differences in spike signaling properties in the axon initial segment and presynaptic boutons of cerebellar interneurons.
abstract: The discrete arrangement of voltage-gated K(+) (Kv) channels in axons may impart functional advantages in action potential (AP) signaling yet, in compact cell types, the organization of Kv channels is poorly understood. We find that in cerebellar stellate cell interneurons of mice, the composition and influence of Kv channels populating the axon is diverse and depends on location allowing axonal compartments to differentially control APs in a local manner. Kv1 channels determine AP repolarization at the spike initiation site but not at more distal sites, limiting the expression of use-dependent spike broadening to the most proximal axon region, likely a key attribute informing spiking phenotype. Local control of AP repolarization at presynaptic boutons depends on Kv3 channels keeping APs brief, thus limiting Ca(2+) influx and synaptic strength. These observations suggest that AP repolarization is tuned by the local influence of distinct Kv channel types, and this organization enhances the functional segregation of axonal compartments.
authors.affiliation: Max Planck Florida Institute for Neuroscience, and Florida Atlantic University, J. D. MacArthur Honors Campus, Jupiter, Florida 33458.
authors.forename: Matthew J M
authors.initials: MJ
authors.lastname: Rowan
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Tranquil
authors.forename: Jason M
authors.initials: JM
authors.lastname: Christie
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology*; D002531:Cerebellum / Q000166:cytology / Q000502:physiology*; D055724:Electrophysiological Phenomena; D005260:Female; D005456:Fluorescent Dyes; D007150:Immunohistochemistry; D007395:Interneurons / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology*; D017729:Presynaptic Terminals / Q000502:physiology*; D018091:Receptors, AMPA / Q000502:physiology; D011963:Receptors, GABA-A / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D017661:Receptors, Presynaptic / Q000502:physiology*; D051637:Shaker Superfamily of Potassium Channels / Q000502:physiology; D051670:Shaw Potassium Channels / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: D005456:Fluorescent Dyes; D015221:Potassium Channels; D018091:Receptors, AMPA; D011963:Receptors, GABA-A; D016194:Receptors, N-Methyl-D-Aspartate; D017661:Receptors, Presynaptic; D051637:Shaker Superfamily of Potassium Channels; D051670:Shaw Potassium Channels