A σ1 receptor pharmacophore derived from a series of N-substituted 4-azahexacyclo[5.4.1.02,6.03,10.05,9.08,11]dodecan-3-ols (AHDs)

A library of N-substituted 4-azahexacyclo[5.4.1.02,6.03,10.05,9.08,11]dodecan-3-ols (AHDs) was synthesized and subjected to competition binding assays at σ1 and σ2 receptors, as well as off-target screening of representative members at 44 other common central nervous system (CNS) receptors, transporters, and ion channels. Excluding 3 low affinity analogs, 31 ligands demonstrated nanomolar Ki values for either σ receptor subtype. Several selective σ1 and σ2 ligands were discovered, with selectivities of up to 29.6 times for σ1 and 52.4 times for σ2, as well as several high affinity, subtype non-selective ligands. The diversity of structures and σ1 affinities of the ligands allowed the generation of a σ1 receptor pharmacophore that will enable the rational design of increasingly selective and potent σ1 ligands for probing σ1 receptor function.