Significantly different effects of tetrahydroberberrubine enantiomers on dopamine D1/D2 receptors revealed by experimental study and integrated in silico simulation

J Comput Aided Mol Des. 2019 Apr;33(4):447-459. doi: 10.1007/s10822-019-00194-z. Epub 2019 Mar 6.


Tetrahydroberberrubine (TU), an active tetrahydroprotoberberines (THPBs), is gaining increasing popularity as a potential candidate for treatment of anxiety and depression. One of its two enantiomers, l-TU, has been reported to be an antagonist of both D1 and D2 receptors, but the functional activity of the other enantiomer, d-TU, is still unknown. In this study, experiments were combined with in silico molecular simulations to (1) confirm and discover the functional activities of l-TU and d-TU, and (2) systematically evaluate the molecular mechanisms beyond the experimental observations. l-TU proved to be an antagonist of both D1 and D2 receptors (IC50 = 385 nM and 985 nM, respectively), while d-TU shows no affinity against either D1 or D2 receptor, based on the cAMP assay (D1 receptor) and calcium flux assay (D2 receptor). Results from both flexible-ligand docking studies and molecular dynamic (MD) simulations provided insights at the atomic level. The l-TU-bound structures predicted by MD (1) undergo an outward rotation of the extracellular helical bundles; (2) have an enlarged orthosteric binding pocket; and (3) have a central toggle switch that is prevented from rotating freely. These features are unique to the l-TU enantiomer and provide an explanation for its antagonistic behavior toward both D1 and D2 receptors. The present study provides new sight on the structural and functional relationships of l-TU and d-TU binding to dopamine receptors, and provides guidance to the rational design of novel molecules targeting these two dopamine receptors in the future.

Keywords: Antagonistic activity; Dopamine receptors; Molecular dynamics simulation; Tetrahydroberberrubine.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Anxiety Agents / pharmacology
  • Antidepressive Agents / pharmacology
  • Berberine / analogs & derivatives*
  • Berberine / chemistry
  • Berberine / pharmacology
  • CHO Cells
  • Cricetulus
  • Dopamine D2 Receptor Antagonists / pharmacology*
  • Drug Design
  • Humans
  • Ligands
  • Molecular Dynamics Simulation
  • Receptors, Dopamine D1 / antagonists & inhibitors*
  • Receptors, Dopamine D1 / metabolism
  • Receptors, Dopamine D2 / metabolism
  • Stereoisomerism


  • Anti-Anxiety Agents
  • Antidepressive Agents
  • Dopamine D2 Receptor Antagonists
  • Ligands
  • Receptors, Dopamine D1
  • Receptors, Dopamine D2
  • Berberine
  • tetrahydroberberrubine