Fig. (2) Docking studies of compounds in σ1R. Compounds A) 2, B) 3, C) 8, D) 12, E) 18 and F) 27. The three amino acids that were found to play a role in binding of the HCD amines were HIS154, GLU172 and TYR120. The aza-HCD moiety provides for the optimal orientation to allow for hydrogen bonding with HIS154 and GLU172.