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The glutamatergic hypothesis of schizophrenia suggests a correlation between NMDA receptor hypofunction and negative psychotic symptoms. It has been observed that the expression of the proline transporter (PROT) in the central nervous system (CNS) is associated with glutamatergic neurotransmission, as L-proline has the capacity to activate and modulate AMPA and NMDA receptors. In this study, we aimed to investigate whether inhibition of proline transporters could enhance glutamatergic neurotransmission and potentially exhibit antipsychotic effects in an experimental schizophrenia model. Using molecular dynamics analysis in silico, we validated an innovative PROT inhibitor, LQFM215. We quantified the cytotoxicity of LQFM215 in the Lund human mesencephalic cell line (LUHMES). Subsequently, we employed the ketamine-induced psychosis model to evaluate the antipsychotic potential of the inhibitor, employing behavioral tests including open-field, three-chamber interaction, and prepulse inhibition (PPI). Our results demonstrate that LQFM215, at pharmacologically active concentrations, exhibited negligible neurotoxicity when astrocytes were co-cultured with neurons. In the ketamine-induced psychosis model, LQFM215 effectively reduced hyperlocomotion and enhanced social interaction in a three-chamber social approach task across all administered doses. Moreover, the compound successfully prevented the ketamine-induced disruption of sensorimotor gating in the PPI test at all tested doses. Overall, these findings suggest that PROT inhibition could serve as a potential therapeutic target for managing symptoms of schizophrenia model.

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Pharmacological manipulation of nitric oxide (NO) has been suggested as a promising treatment for schizophrenia symptoms. A single infusion of sodium nitroprusside, a NO donor with short half-life, was found to improve schizophrenia symptoms. However, an increasing number of preclinical studies have demonstrated the potential beneficial effects of both NO donors and inhibitors. We investigated the potential synergistic effect of sub-effective doses of the NO donor sodium nitroprusside or the NO inhibitor 7-Nitroindazole (7NI) combined with clozapine, a standard atypical antipsychotic, on counteracting amphetamine or MK-801-induced psychosis-like behaviors. The impact of sodium nitroprusside and 7NI on cAMP regulation in the prefrontal cortex and striatum was also evaluated. Confirming previous results, we found that both NO donors and inhibitors prevented amphetamine-induced effects (prepulse inhibition [PPI] disruption and hyperlocomotion). In addition, we observed a synergistic effect of sodium nitroprusside and clozapine on antagonizing the disruptive effects of amphetamine, but not MK-801, in the PPI test. The sub-effective dose of 7NI tested did not prevent amphetamine or MK-induced PPI effects when combined with clozapine. Interestingly, cAMP levels were significantly decreased in the prefrontal cortex after treatment with sodium nitroprusside. In the striatum, both sodium nitroprusside and 7NI blocked the amphetamine-induced increase of cAMP. Our data corroborate previous findings on the dopaminergic mechanisms involved in the action of sodium nitroprusside. It is likely that the differential effects of sodium nitroprusside are related to its ability to modify cAMP levels in the prefrontal cortex.

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O canabidiol, fitocanabinóide presente na planta Cannabis sativa é desprovido dos efeitos psicotomiméticos característicos do principal composto da Cannabis, o ∆9-tetraidrocanabinol, mais conhecido como delta 9-THC. Um conjunto crescente de evidências sugere que o canabidiol apresente potencial terapêutico para o tratamento dos sintomas de distúrbios psiquiátricos, como a depressão, a ansiedade e as psicoses. A observação em humanos, mas também em modelos animais experimentais da capacidade do canabidiol de antagonizar os efeitos psicotomiméticos do delta 9-THC constitui uma importante evidência de seu potencial para utilização clínica. Embora os efeitos farmacológicos do canabidiol tenham sido investigados em diferentes sistemas biológicos in vitro e in vivo, seu mecanismo de ação ainda não é claro. O delta 9-THC ativa os receptores canabinóides do tipo CB1 e CB2, contudo o canabidiol apresenta uma baixa afinidade por esses receptores. Adicionalmente, o canabidiol em apresentado boa tolerabilidade em testes com humanos, tornando-o alvo de grande interesse da comunidade científica. O objetivo dessa revisão é apresentar, de forma breve, algumas das principais evidências experimentais e clínicas do provável perfil antipsicótico do canabidiol...

Cannabidiol an important phytocannabinoid present in the Cannabis sativa opposing to the major plant compound D9-tetrahydrocannabinol, known as delta-9-THC, is devoid of the psychotomimetic effects. Growing set of evidence suggest that cannabidiol may be used for the treatment of the symptoms of psychiatric disorders such as depression, anxiety and psychosis. The first evidence of the cannabidiol therapeutic potential was the observation of its ability to antagonize delta-9-THC effects either on human and experimental animal models. Pharmacological effects of CBD has been investigated in different biological systems, in vitro and in vivo, however, the mechanisms responsible for their therapeutic potential are still unclear. delta-9-THC effects results from activation of the cannabinoid receptors CB1 and CB2, however, the cannabidiol has low affinity for these receptors. The good tolerability of cannabidiolin human trials makes this compound an interesting target of the scientific community. The aim of this paper is to present concisely some experimental and clinical evidence about the cannabidiol antipsychotic profile...

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