No abstract

In the scope of a research program aimed at developing new drugs for the treatment of central nervous system diseases, we describe herein the synthesis and pharmacological evaluation of 1-(4-(3,5-di-tert-butyl-4-hydroxybenzyl) piperazin-1-yl)-2-methoxyethan-1-one (LQFM180). This compound showed antioxidant activity in two models, electroanalytical assays, and DPPH activity. Moreover, in behavioral tests as the open field test LQFM180 (9.4, 18.8, and 37.6 mg/kg, per oral (p.o.)), we detected anxiolytic-like activity. In the sodium pentobarbital-induced sleep test, LQFM180, in all doses, decreased the latency to sleep and increased sleep duration, indicating central depressant activity; moreover, in the chimney test, LQFM180 did not alter motor activity. LQFM180 (18.8 mg/kg, p.o.) increased the time and number of entries on open arms in the elevated plus maze test, suggesting anxiolytic-like activity, which was reversed by NAN-190 and p-chlorophenylalanine, indicating a role of the serotonergic pathway on this effect. In the forced swimming test, LFQM180 (18.8 mg/kg, p.o.) decreased immobility time, suggesting antidepressant-like activity, which was reversed by monoaminergic antagonists, indicating a role for the serotonergic, noradrenergic, and dopaminergic pathways. Competition binding assays showed that LQFM180 was able to bind to the α, 5-HT, and D receptors, however, within the low micromolar range. We conclude that LQFM180 should be considered as a scaffold for drug candidate development.

LASSBio-579, an N -phenylpiperazine antipsychotic lead compound, has been previously reported as a D 2 receptor (D 2 R) 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 D 2 R. HEK-293T cells transiently coexpressing the human long isoform of D 2 receptor (D 2 LR) 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 D 2 R 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.