ABSTRACT
The GABA(A) receptor subtypes responsible for the anxiolytic effects of nonselective benzodiazepines (BZs) such as chlordiazepoxide (CDP) and diazepam remain controversial. Hence, molecular genetic data suggest that alpha2-rather than alpha3-containing GABA(A) receptors are responsible for the anxiolytic effects of diazepam, whereas the anxiogenic effects of an alpha3-selective inverse agonist suggest that an agonist selective for this subtype should be anxiolytic. We have extended this latter pharmacological approach to identify a compound, 4,2'-difluoro-5'-[8-fluoro-7-(1-hydroxy-1-methylethyl)imidazo[1,2-á]pyridin-3-yl]biphenyl-2-carbonitrile (TP003), that is an alpha3 subtype selective agonist that produced a robust anxiolytic-like effect in both rodent and non-human primate behavioral models of anxiety. Moreover, in mice containing a point mutation that renders alpha2-containing receptors BZ insensitive (alpha2H101R mice), TP003 as well as the nonselective agonist CDP retained efficacy in a stress-induced hyperthermia model. Together, these data show that potentiation of alpha3-containing GABA(A) receptors is sufficient to produce the anxiolytic effects of BZs and that alpha2 potentiation may not be necessary.
Subject(s)
Anti-Anxiety Agents/therapeutic use , Benzodiazepines/therapeutic use , Protein Subunits/physiology , Receptors, GABA-A/physiology , Animals , Anti-Anxiety Agents/pharmacology , Anxiety/drug therapy , Anxiety/metabolism , Benzodiazepines/pharmacology , Dose-Response Relationship, Drug , GABA-A Receptor Agonists , Humans , Male , Mice , Mice, Transgenic , Protein Binding/physiology , Rats , Rats, Sprague-Dawley , SaimiriABSTRACT
A new series of gamma-secretase inhibitors was developed from an in-house screening hit based on a benzobicyclo[4.2.1]nonane core. Lead optimisation studies led to the development of a series of potent inhibitors and in vivo efficacy was demonstrated.
