Boehringer Ingelheim and Arena Pharmaceuticals will conduct joint research to identify drug candidates targeting an undisclosed G protein-coupled receptor (GPCR), which belongs to the group of orphan CNS receptors. An “orphan receptor” is structurally related to a family of proteins that are known to act as functional cell-surface receptors but whose ligand has not yet been identified. Arena will provide Boehringer Ingelheim exclusive rights to its internally discovered, novel com...