Carbazole and tetrahydro-carboline derivatives as dopamine D_(3) receptor antagonists with the multiple antipsychotic-like properties

Dopamine D_(3) receptor(D_(3)R)is implicated in multiple psychotic symptoms.Increasing the D_(3)R selectivity over dopamine D_2 receptor(D_2R)would facilitate the antipsychotic treatments.Herein,novel carbazole and tetrahydro-carboline derivatives were reported as D_(3)R selective ligands.Through a structure-based virtual screen,ZLG-25(D_(3)R K_i=685 nmol/L;D_2R K_i>10,000 nmol/L)was identified as a novel D_(3)R selective bitopic ligand with a carbazole scaffold.Scaffolds hopping led to the discovery of novel D_(3)R-selective analogs with tetrahydro-β-carboline or tetrahydro-γ-carboline core.Further functional studies showed that most derivatives acted as h D_(3)R-selective antagonists.Several lead compounds could dose-dependently inhibit the MK-801-induced hyperactivity.Additional investigation revealed that 23j and 36b could decrease the apomorphine-induced climbing without cataleptic reaction.Furthermore,36b demonstrated unusual antidepressant-like activity in the forced swimming tests and the tail suspension tests,and alleviated the MK-801-induced disruption of novel object recognition in mice.Additionally,preliminary studies confirmed the favorable PK/PD profiles,no weight gain and limited serum prolactin levels in mice.These results revealed that 36b provided potential opportunities to new antipsychotic drugs with the multiple antipsychotic-like properties.