RESUMO
As part of our ongoing research to identify novel agents acting at metabotropic glutamate 2 (mGlu2) and 3 (mGlu3) receptors, we have previously reported the identification of the C4α-methyl analog of mGlu2/3 receptor agonist 1 (LY354740). This molecule, 1S,2S,4R,5R,6S-2-amino-4-methylbicyclo[3.1.0]hexane-2,6-dicarboxylate 2 (LY541850), exhibited an unexpected mGlu2 agonist/mGlu3 antagonist pharmacological profile, whereas the C4ß-methyl diastereomer (3) possessed dual mGlu2/3 receptor agonist activity. We have now further explored this structure-activity relationship through the preparation of cyclic and acyclic C4-disubstituted analogs of 1, leading to the identification of C4-spirocyclopropane 5 (LY2934747), a novel, potent, and systemically bioavailable mGlu2/3 receptor agonist which exhibits both antipsychotic and analgesic properties in vivo. In addition, through the combined use of protein-ligand X-ray crystallography employing recombinant human mGlu2/3 receptor amino terminal domains, molecular modeling, and site-directed mutagenesis, a molecular basis for the observed pharmacological profile of compound 2 is proposed.
Assuntos
Compostos Bicíclicos com Pontes/farmacologia , Receptores de Glutamato Metabotrópico/agonistas , Compostos de Espiro/farmacologia , Animais , Compostos Bicíclicos com Pontes/química , Compostos Bicíclicos com Pontes/metabolismo , Cristalografia por Raios X , Humanos , Masculino , Modelos Moleculares , Estrutura Terciária de Proteína , Ratos , Ratos Sprague-Dawley , Receptores de Glutamato Metabotrópico/química , Receptores de Glutamato Metabotrópico/genética , Compostos de Espiro/química , Compostos de Espiro/metabolismoRESUMO
A series of benzylic piperazines (e.g., 4 and 5) attached to an 'address element', the dipeptide H-D-Tic-D-p-Cl-Phe-OH, 3 has been identified as ligands for the melanocortin subtype-4 receptor (MC4R). We describe herein the structure-activity relationship (SAR) studies on the N-terminal residue of the 'address element'. Several novel dipeptides and reduced dipeptides with high MC4R binding affinities and selectivity emerged from this SAR study.