Developmental expression of potassium‐channel subunit Kv3.2 within subpopulations of mouse hippocampal inhibitory interneurons
- 1 January 2002
- journal article
- Published by Wiley in Hippocampus
- Vol. 12 (2), 137-148
- https://doi.org/10.1002/hipo.1104
Abstract
The developmental expression of the voltage‐gated potassium channel subunit, Kv3.2, and its localization within specific mouse hippocampal inhibitory interneuron populations were determined using immunoblotting and immunohistochemical techniques. Using immunoblotting techniques, the Kv3.2 protein was weakly detected at postnatal age day 7 (P7), and full expression was attained at P21 in tissue extracts from homogenized hippocampal preparations. A similar developmental profile was observed using immunohistochemical techniques in hippocampal tissue sections. Kv3.2 protein expression was clustered on the somata and proximal dendrites of presumed inhibitory interneurons. Using double immunofluorescence, Kv3.2 subunit expression was detected on subpopulations of GABAergic inhibitory interneurons. Kv3.2 was detected in ∼100% of parvalbumin‐positive interneurons, 86% of interneurons expressing nitric oxide synthase, and ∼50% of somatostatin‐immunoreactive cells. Kv3.2 expression was absent from both calbindin‐ and calretinin‐containing interneurons. Using immunoprecipitation, we further demonstrate that Kv3.2 and its related subunit Kv3.1b are coexpressed within the same protein complexes in the hippocampus. These data demonstrate that potassium channel subunit Kv3.2 expression is developmentally regulated in a specific set of interneurons. The vast majority of these interneuron subpopulations possess a “fast‐spiking” phenotype, consistent with a role for currents through Kv3.2 containing channels in determining action potential kinetics in these cells. Hippocampus 2002;12:137–148. Published 2002 Wiley‐Liss, Inc.Keywords
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