KCTD12 Auxiliary Proteins Modulate Kinetics of GABA(B) Receptor-Mediated Inhibition in CholecystokininContaining Interneurons



Booker, Sam A, Althof, Daniel, Gross, Anna, Loreth, Desiree, Mueller, Johanna, Unger, Andreas, Fakler, Bernd, Varro, Andrea, Watanabe, Masahiko, Gassmann, Martin
et al (show 4 more authors) (2017) KCTD12 Auxiliary Proteins Modulate Kinetics of GABA(B) Receptor-Mediated Inhibition in CholecystokininContaining Interneurons. Cerebral Cortex, 27 (3). 2318 - 2334.

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Abstract

Cholecystokinin-expressing interneurons (CCK-INs) mediate behavior state-dependent inhibition in cortical circuits and themselves receive strong GABAergic input. However, it remains unclear to what extent GABAB receptors (GABABRs) contribute to their inhibitory control. Using immunoelectron microscopy, we found that CCK-INs in the rat hippocampus possessed high levels of dendritic GABABRs and KCTD12 auxiliary proteins, whereas postsynaptic effector Kir3 channels were present at lower levels. Consistently, whole-cell recordings revealed slow GABABR-mediated inhibitory postsynaptic currents (IPSCs) in most CCK-INs. In spite of the higher surface density of GABABRs in CCK-INs than in CA1 principal cells, the amplitudes of IPSCs were comparable, suggesting that the expression of Kir3 channels is the limiting factor for the GABABR currents in these INs. Morphological analysis showed that CCK-INs were diverse, comprising perisomatic-targeting basket cells (BCs), as well as dendrite-targeting (DT) interneurons, including a previously undescribed DT type. GABABR-mediated IPSCs in CCK-INs were large in BCs, but small in DT subtypes. In response to prolonged activation, GABABR-mediated currents displayed strong desensitization, which was absent in KCTD12-deficient mice. This study highlights that GABABRs differentially control CCK-IN subtypes, and the kinetics and desensitization of GABABR-mediated currents are modulated by KCTD12 proteins.

Item Type: Article
Uncontrolled Keywords: desensitization, disinhibition, immunoelectron microscopy, Kir3 channels, network activity
Depositing User: Symplectic Admin
Date Deposited: 13 Jun 2018 08:37
Last Modified: 27 Nov 2020 10:11
DOI: 10.1093/cercor/bhw090
Open Access URL: http://doi.org/10.1093/cercor/bhw090
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URI: http://livrepository.liverpool.ac.uk/id/eprint/3022508