Y-QA31, a novel dopamine D3 receptor antagonist, exhibits antipsychotic-like properties in preclinical animal models of schizophrenia.

AIM: To investigate the potential effects of Y-QA31, a novel dopamine D3 receptor antagonist, as an antipsychotic drug.
METHODS: A panel of radioligand-receptor binding assays was performed to identify the affinities of Y-QA31 for different G protein-coupled receptors. [(35)S]GTPγS-binding assays and Ca(2+) imaging were used to assess its intrinsic activities. The antipsychotic profile of Y-QA31 was characterized in mouse models for the positive symptoms and cognitive deficits of schizophrenia and extrapyramidal side effects with haloperidol and clozapine as positive controls.
RESULTS: In vitro, Y-QA31 is a dopamine D3 receptor antagonist that is 186-fold more potent at the D3 receptor than at the D2 receptor. Y-QA31 also exhibits 5-HT1A receptor partial agonist and α1A adrenoceptor antagonist activities with medium affinity, whereas it exhibits very little affinity for other receptors (100-fold lower than for the D3 receptor). In vivo, Y-QA31 (10-40 mg/kg, po) significantly inhibited MK-801-induced hyperlocomotion and methamphetamine-induced prepulse inhibition disruption in a dose-dependent manner. Y-QA31 also inhibited the avoidance response and methamphetamine-induced hyperlocomotion with potency lower than haloperidol. Y-QA31 was effective in alleviating the MK-801-induced disruption of novel object recognition at a low dose (1 mg/kg, po). Moreover, Y-QA31 itself did not affect spontaneous locomotion or induce cataleptic response until its dose reached 120 mg/kg.
CONCLUSION: Y-QA31 is a selective D3R antagonist that exhibits antipsychotic effects in some animal models with positive symptoms and cognitive disorder and less extrapyramidal side effects.