Distinct axo‐somato‐dendritic distributions of three potassium channels inCA 1 hippocampal pyramidal cells
| Autor: | Zoltan Nusser, Tekla Kirizs, Andrea Lorincz, Katalin Kerti-Szigeti |
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| Rok vydání: | 2014 |
| Předmět: |
Male
Dendritic spine Protein subunit Biology Hippocampal formation confocal microscopy Shab Potassium Channels medicine Animals Rats Wistar Axon CA1 Region Hippocampal Cells Cultured Ion channel electron microscopy Pyramidal Cells General Neuroscience ion channels Dendrites Axon initial segment Axons Potassium channel Rats Cell biology Protein Transport medicine.anatomical_structure G Protein-Coupled Inwardly-Rectifying Potassium Channels immunohistochemistry Soma Special Issue: Editors' Issue 2014 Kv1.1 Potassium Channel |
| Zdroj: | European Journal of Neuroscience The European Journal of Neuroscience |
| ISSN: | 1460-9568 0953-816X |
| DOI: | 10.1111/ejn.12526 |
| Popis: | Potassium channels comprise the most diverse family of ion channels and play critical roles in a large variety of physiological and pathological processes. In addition to their molecular diversity, variations in their distributions and densities on the axo-somato-dendritic surface of neurons are key parameters in determining their functional impact. Despite extensive electrophysiological and anatomical investigations, the exact location and densities of most K(+) channels in small subcellular compartments are still unknown. Here we aimed at providing a quantitative surface map of two delayed-rectifier (Kv1.1 and Kv2.1) and one G-protein-gated inwardly rectifying (Kir3.2) K(+) channel subunits on hippocampal CA1 pyramidal cells (PCs). Freeze-fracture replica immunogold labelling was employed to determine the relative densities of these K(+) channel subunits in 18 axo-somato-dendritic compartments. Significant densities of the Kv1.1 subunit were detected on axon initial segments (AISs) and axon terminals, with an approximately eight-fold lower density in the latter compartment. The Kv2.1 subunit was found in somatic, proximal dendritic and AIS plasma membranes at approximately the same densities. This subunit has a non-uniform plasma membrane distribution; Kv2.1 clusters are frequently adjacent to, but never overlap with, GABAergic synapses. A quasi-linear increase in the Kir3.2 subunit density along the dendrites of PCs was detected, showing no significant difference between apical dendritic shafts, oblique dendrites or dendritic spines at the same distance from the soma. Our results demonstrate that each subunit has a unique cell-surface distribution pattern, and predict their differential involvement in synaptic integration and output generation at distinct subcellular compartments. |
| Databáze: | OpenAIRE |
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