Distribution and functional expression of Kv4 family α subunits and associated KChIP β subunits in the bed nucleus of the stria terminalis. Issue 3 (15th February 2014)

• Record Type: Journal Article
• Authors: Rainnie, Donald G.; Hazra, Rimi; Dabrowska, Joanna; Guo, Ji‐Dong; Li, Chen Chen; Dewitt, Sarah; Muly, E. Chris
• Is Part Of: Journal of comparative neurology. Volume 522:Issue 3(2014:Feb. 15)
• Page Start: 609
• Page End: 625
• Publication Date: 2014-02-15
• Subjects: Comparative neurobiology -- Periodicals; Neurology -- Periodicals; 616
• DOI: 10.1002/cne.23435
• Languages: English
• ISSNs: 0021-9967

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Regulation of BNST<sub>ALG</sub> neuronal firing activity is tightly regulated by the opposing actions of the fast outward potassium current, I<sub>A</sub>, mediated by α subunits of the Kv4 family of ion channels, and the transient inward calcium current, I<sub>T</sub>. Together, these channels play a critical role in regulating the latency to action potential onset, duration, and frequency, as well as dendritic back‐propagation and synaptic plasticity. Previously we have shown that Type I–III BNST<sub>ALG</sub> neurons express mRNA transcripts for each of the Kv4 α subunits. However, the biophysical properties of native I<sub>A</sub> channels are critically dependent on the formation of macromolecular complexes of Kv4 channels with a family of chaperone proteins, the potassium channel‐interacting proteins (KChIP1–4). Here we used a multidisciplinary approach to investigate the expression and function of Kv4 channels and KChIPs in neurons of the rat BNST<sub>ALG</sub>. Using immunofluorescence we demonstrated the pattern of localization of Kv4.2, Kv4.3, and KChIP1–4 proteins in the BNST<sub>ALG</sub>. Moreover, our single‐cell reverse‐transcription polymerase chain reaction (scRT‐PCR) studies revealed that mRNA transcripts for Kv4.2, Kv4.3, and all four KChIPs were differentially expressed in Type I–III BNST<sub>ALG</sub> neurons. Furthermore, immunoelectron microscopy revealed that Kv4.2 and Kv4.3 channels were primarily localized to the dendrites and spines of BNST<sub>ALG</sub> neurons, and are thus ideally situated to modulate synaptic transmission. Consistent with this observation, in vitro patch clamp recordings showed that reducing postsynaptic I<sub>A</sub> in these neurons lowered the threshold for long‐term potentiation (LTP) induction. These results are discussed in relation to potential modulation of I<sub>A</sub> channels by chronic stress. J. Comp. Neurol. 522:609–625, 2014. © 2013 Wiley Periodicals, Inc.</p> </abstract>