Tetrahydroisoquinolines acting as dopaminergic ligands. A molecular modeling study using MD simulations and QM calculations.

A molecular modeling study on 16 1-benzyl tetrahydroisoquinolines (BTHIQs) acting as dopaminergic ligands was carried out. By combining molecular dynamics simulations with ab initio and density functional theory (DFT) calculations, a simple and generally applicable procedure to evaluate the binding energies of BTHIQs interacting with the human dopamine D2 receptor (D2 DR) is reported here, providing a clear picture of the binding interactions of BTHIQs from both structural and energetic viewpoints. Molecular aspects of the binding interactions between BTHIQs and the D2 DR are discussed in detail. A significant correlation between binding energies obtained from DFT calculations and experimental pKi values was obtained, predicting the potential dopaminergic effect of non-synthesized BTHIQs.