Development and SAR of functionally selective allosteric modulators of GABAA receptors

Positive modulators at the benzodiazepine site of alpha 2- and alpha 3-containing GABA(A) receptors are believed to be anxiolytic. Through oocyte voltage clamp studies, we have discovered two series of compounds that are positive modulators at alpha 2-/alpha 3-containing GABA(A) receptors and that show no functional activity at alpha 1-containing GABAA receptors. We report studies to improve this functional selectivity and ultimately deliver clinical candidates. The functional SAR of cinnolines and quinolines that are positive allosteric modulators of the alpha 2- and alpha 3-containing GABA(A) receptors, while simultaneously neutral antagonists at alpha 1-containing GABAA receptors, is described. Such functionally selective modulators of GABA(A) receptors are expected to be useful in the treatment of anxiety and other psychiatric illnesses. (C) 2011 Elsevier Ltd. All rights reserved.