文章基本信息

标题：Discovery of a new class of orthosteric antagonists with nanomolar potency at extrasynaptic GABA A receptors
本地全文：下载
作者：Christina Birkedahl Falk-Petersen ; Tsonko M. Tsonkov ; Malene Sofie Nielsen 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2020
卷号：10
期号：1
页码：1-12
DOI：10.1038/s41598-020-66821-0
出版社：Springer Nature
摘要：Brain GABAΑ receptors are ionotropic receptors belonging to the class of Cys-loop receptors and are important drug targets for the treatment of anxiety and sleep disorders. By screening a compound library (2,112 compounds) at recombinant human α4β1δ GABAΑ receptors heterologously expressed in a HEK cell line, we identified a scaffold of spirocyclic compounds with nanomolar antagonist activity at GABAΑ receptors. The initial screening hit 2027 (IC50 of 1.03 μM) was used for analogue search resulting in 018 (IC50 of 0.088 μM). 018 was most potent at α3,4,5-subunit containing receptors, thus showing preference for forebrain-expressed extrasynaptic receptors. Schild analysis of 018 at recombinant human α4β1δ receptors and displacement of [3H]muscimol binding in rat cortical homogenate independently confirmed a competitive profile. The antagonist profile of 018 was further validated by whole-cell patch-clamp electrophysiology, where kinetic studies revealed a slow dissociation rate and a shallow hill slope was observed. Membrane permeability studies showed that 2027 and 018 do not cross membranes, thus making the compounds less attractive for studying central GABAΑ receptors effects, but conversely more attractive as tool compounds in relation to emerging peripheral GABAΑ receptor-mediated effects of GABA e.g. in the immune system.