Buspirone Counteracts MK-801-Induced Schizophrenia-Like Phenotypes through Dopamine D Receptor Blockade.

Several efforts have been made to develop effective antipsychotic drugs. Currently, available antipsychotics are effective on positive symptoms, less on negative symptoms, but not on cognitive impairment, a clinically relevant dimension of schizophrenia. Drug repurposing offers great advantages over the long-lasting, risky and expensive, drug discovery strategy. To our knowledge, the possible antipsychotic properties of buspirone, an azapirone anxiolytic drug marketed in 1986 as serotonin 5-HT receptor (5-HTR) partial agonist, have not been extensively investigated despite its intriguing pharmacodynamic profile, which includes dopamine D (DR) and D receptor (DR) antagonist activity. Multiple lines of evidence point to DR as a valid therapeutic target for the treatment of several neuropsychiatric disorders including schizophrenia. In the present study, we tested the hypothesis that buspirone, behaving as dopamine DR antagonist, may have antipsychotic-like activity. Effects of acute administration of buspirone was assessed on a wide-range of schizophrenia-relevant abnormalities induced by a single administration of the non-competitive NMDAR antagonist MK-801, in both wild-type mice (WT) and DR-null mutant mice (DR). Buspirone (3 mg⋅kg, i.p.) was devoid of cataleptogenic activity in itself, but resulted effective in counteracting disruption of prepulse inhibition (PPI), hyperlocomotion and deficit of temporal order recognition memory (TOR) induced by MK-801 (0.1 mg⋅kg, i.p.) in WT mice. Conversely, in DR mice, buspirone was ineffective in preventing MK-801-induced TOR deficit and it was only partially effective in blocking MK-801-stimulated hyperlocomotion. Taken together, these results indicate, for the first time, that buspirone, might be a potential therapeutic medication for the treatment of schizophrenia. In particular, buspirone, through its DR antagonist activity, may be a useful tool for improving the treatment of cognitive deficits in schizophrenia that still represents an unmet need of this disease.