Evaluation of Functional Selectivity of Haloperidol, Clozapine, and LASSBio-579, an Experimental Compound With Antipsychotic-Like Actions in Rodents, at G Protein and Arrestin Signaling Downstream of the Dopamine D2 Receptor

• Main Authors: Rafaela R. Silva (Author), Lucas T. Parreiras- (Author), Thais E.T. Pompeu (Author), Diego A. Duarte (Author), Carlos A.M. Fraga (Author), Eliezer J. Barreiro (Author), Ricardo Menegatti (Author), Claudio M. Costa-Neto (Author), François Noël (Author)
• Format: Book
• Published: Frontiers Media S.A., 2019-06-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 1663-9812; 10.3389/fphar.2019.00628
• Keywords: LASSBio-579; D2; schizophrenia; antipsychotics; β-arrestin; functional selectivity; Therapeutics. Pharmacology; RM1-950
• Source: Frontiers in Pharmacology, Vol 10 (2019)

LASSBio-579, an N-phenylpiperazine antipsychotic lead compound, has been previously reported as a D2 receptor (D2R) ligand with antipsychotic-like activities in rodent models of schizophrenia. In order to better understand the molecular mechanism of action of LASSBio-579 and of its main metabolite, LQFM 037, we decided to address the hypothesis of functional selectivity at the D2R. HEK-293T cells transiently coexpressing the human long isoform of D2 receptor (D2LR) and bioluminescence resonance energy transfer (BRET)-based biosensors were used. The antagonist activity was evaluated using different concentrations of the compounds in the presence of a submaximal concentration of dopamine (DA), after 5 and 20 min. For both signaling pathways, haloperidol, clozapine, and our compounds act as DA antagonists in a concentration-dependent manner, with haloperidol being by far the most potent, consistent with its nanomolar D2R affinity measured in binding assays. In our experimental conditions, only haloperidol presented a robust functional selectivity, being four- to fivefold more efficient for inhibiting translocation of β-arrestin-2 (β-arr2) than for antagonizing Gi activation. Present data are the first report on the effects of LASSBio-579 and LQFM 037 on the β-arr2 signaling pathway and further illustrate that the functional activity could vary depending on the assay conditions and approaches used.