Investigation of key interactions between the second extracellular loop of dopamine D2 receptor and several hydroxy-N-{[2-(4-phenyl-piperaziny-1-yl)ethyl]phenyl}-nicotinamides

Abstract

The dopaminergic receptor system has been the focus for the development of new pharmacotherapeutic agents targeting a number of central nervous system related disorders, such as drug addiction, schizophrenia, depression, and Parkinson's disease, to name just a few. To date, the crystal structure for the human D2 receptor is not known, despite its vital function and importance as a therapeutic target. Herein, a recent advancement in the determination of key receptor ligand interactions for the available arylpiperazine-like ligands, using a D2 receptor model based on the crystal structure of the D3 receptor is presented. To determine key interactions responsible for high dopaminergic activity, computer-docking analysis was used together with experimental data. A total of 4 dopaminergic ligands showing moderate to high affinity were tested and the obtained results rationalized using ligand structures docked into the proposed D2 receptor model.