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Free keywords:
Animals
Axons
Cerebellum
Electrophysiological Processes
Female
Fluorescent Dyes
Immunohistochemistry
Interneurons
Male
Mice
Mice, Inbred C57BL
Microscopy, Fluorescence
Patch-Clamp Techniques
Potassium Channels
Presynaptic Terminals
Receptors, AMPA
Receptors, GABA-A
Receptors, N-Methyl-D-Aspartate
Receptors, Presynaptic
Shaker Superfamily of Potassium Channels
Shaw Potassium Channels
synaptic transmission
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.
