RESUMO
As part of our efforts to develop CB2 PET imaging agents, we investigated 2,5,6-substituted pyridines as a novel class of potential CB2 PET ligands. A total of 21 novel compounds were designed, synthesized, and evaluated for their potency and binding properties toward human and rodent CB1 and CB2. The most promising ligand 6a was radiolabeled with carbon-11 to yield 16 ([(11)C]RSR-056). Specific binding of 16 to CB2-positive spleen tissue of rats and mice was demonstrated by in vitro autogadiography and verified in vivo in PET and biodistribution experiments. Furthermore, 16 was evaluated in a lipopolysaccharid (LPS) induced murine model of neuroinflammation. Brain radioactivity was strikingly higher in the LPS-treated mice than the control mice. Compound 16 is a promising radiotracer for imaging CB2 in rodents. It might serve as a tool for the investigation of CB2 receptor expression levels in healthy tissues and different neuroinflammatory disorders in humans.
Assuntos
Meios de Contraste/química , Meios de Contraste/farmacocinética , Tomografia por Emissão de Pósitrons/métodos , Receptor CB2 de Canabinoide/análise , Animais , Azetidinas/química , Azetidinas/farmacocinética , Células CHO , Cricetulus , Descoberta de Drogas , Avaliação Pré-Clínica de Medicamentos/métodos , Estabilidade de Medicamentos , Humanos , Masculino , Camundongos Endogâmicos , Ácidos Picolínicos/química , Ácidos Picolínicos/farmacocinética , Piridinas/química , Ratos Wistar , Receptor CB1 de Canabinoide/análise , Receptor CB1 de Canabinoide/genética , Receptor CB1 de Canabinoide/metabolismo , Receptor CB2 de Canabinoide/genética , Receptor CB2 de Canabinoide/metabolismo , Distribuição TecidualRESUMO
A series of highly potent & selective adamantane derived CB2 agonists was identified in a high-throughput screen. A SAR was established and physicochemical properties were significantly improved. This was accompanied by potency of the compounds on the Q63R variant and varying ß-arrestin data which will support the insight into their relevance for the in vivo situation.