Mechanisms underlying the activation of G-protein-gated inwardly rectifying K+ (GIRK) channels by the novel anxiolytic drug, ML297.

Wydeven N, Marron Fernandez de Velasco E, Du Y, Benneyworth MA, Hearing MC, Fischer RA, Thomas MJ, Weaver CD, Wickman K
Proc Natl Acad Sci U S A. 2014 111 (29): 10755-60

PMID: 25002517 · PMCID: PMC4115558 · DOI:10.1073/pnas.1405190111

ML297 was recently identified as a potent and selective small molecule agonist of G-protein-gated inwardly rectifying K(+) (GIRK/Kir3) channels. Here, we show ML297 selectively activates recombinant neuronal GIRK channels containing the GIRK1 subunit in a manner that requires phosphatidylinositol-4,5-bisphosphate (PIP2), but is otherwise distinct from receptor-induced, G-protein-dependent channel activation. Two amino acids unique to the pore helix (F137) and second membrane-spanning (D173) domain of GIRK1 were identified as necessary and sufficient for the selective activation of GIRK channels by ML297. Further investigation into the behavioral effects of ML297 revealed that in addition to its known antiseizure efficacy, ML297 decreases anxiety-related behavior without sedative or addictive liabilities. Importantly, the anxiolytic effect of ML297 was lost in mice lacking GIRK1. Thus, activation of GIRK1-containing channels by ML297 or derivatives may represent a new approach to the treatment of seizure and/or anxiety disorders.

MeSH Terms (14)

Amino Acid Sequence Animals Anti-Anxiety Agents Baclofen Behavior, Animal G Protein-Coupled Inwardly-Rectifying Potassium Channels Hippocampus Ion Channel Gating Mice Mice, Inbred C57BL Molecular Sequence Data Neurons Phenylurea Compounds Pyrazoles

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