Expression and distribution of Kv4 potassium channel subunits and potassium channel interacting proteins in subpopulations of interneurons in the basolateral amygdala

• Type of Material: Article
• Authors: Joanna Alicja Dabrowska, Emory University; Donald Rainnie, Emory University
• Language: English
• Date: 2010-12-15
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2010 IBRO. Published by Elsevier Ltd. All rights reserved
• License: Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1016/j.neuroscience.2010.09.011
• Title of Journal or Parent Work: Neuroscience
• ISSN: 0306-4522
• Volume: 171
• Issue: 3
• Start Page: 721
• End Page: 733
• Grant/Funding Information: This work was supported by National Institute of Mental Health Grant MH069852 to D.G. Rainnie; the Science and Technology Centers Integrative Partnership Program of the National Science Foundation (The Center for Behavioral Neuroscience) Grant IBN-987675; and the Yerkes National Primate Research Center Base Grant RR-00165 awarded by the Animal Resources Program of National Institutes of Health.
• Keywords: BLA; NPY; parvalbumin; CCK-8; somatostatin; KChIP1
• Research Categories: Biology, Neuroscience

Abstract

Kv4 potassium channel α subunits, Kv4.1, Kv4.2, and Kv4.3, determine some of the fundamental physiological properties of neurons in the CNS. Kv4 subunits are associated with auxiliary β-subunits, such as the potassium channel interacting proteins (KChIP1 – 4), which are thought to regulate the trafficking and gating of native Kv4 potassium channels. Intriguingly, KChIP1 is thought to show cell type-selective expression in GABA-ergic inhibitory interneurons, while other β-subunits (KChIP2–4) are associated with principal glutamatergic neurons. However, nothing is known about the expression of Kv4 family α- and β-subunits in specific interneurons populations in the BLA. Here, we have used immunofluorescence, co-immunoprecipitation, and Western Blotting to determine the relative expression of KChIP1 in the different interneuron subtypes within the BLA, and its co-localization with one or more of the Kv4 α subunits. We show that all three α-subunits of Kv4 potassium channel are found in rat BLA neurons, and that the immuno-reactivity of KChIP1 closely resembles that of Kv4.3. Indeed, Kv4.3 showed almost complete co-localization with KChIP1 in the soma and dendrites of a distinct subpopulation of BLA neurons. Dual-immunofluorescence studies revealed this to be in BLA interneurons immunoreactive for parvalbumin, cholecystokin-8, and somatostatin. Finally, co-immunoprecipitation studies showed that KChIP1 was associated with all three Kv4 α subunits. Together our results suggest that KChIP1 is selectively expressed in BLA interneurons where it may function to regulate the activity of A-type potassium channels. Hence, KChIP1 might be considered as a cell type-specific regulator of GABAergic inhibitory circuits in the BLA.