From α4β2 Nicotinic Ligands to the Discovery of σ1 Receptor Ligands: Pharmacophore Analysis and Rational Design

Comparative analyses of the pharmacophoric elements required for sigma 1 and nicotinic ligands led to the identification of a potent and selective sigma 1 ligand (15). Compound 15 displayed high selectivity for the sigma 1 receptor (K-i, sigma 1 = 4.1 nM; K-i, sigma 2 = 1312 nM) with moderate binding affinity for the DAT (K-i = 373 nM) and NET (K-i = 203 nM) in the PDSP broad screening panel of common CNS neurotransmitter transporters and receptors. The key finding in this present work is that a subtle structural modification could be used as a tool to switch a ligand's selectivity between nAChRs and sigma receptors.