Navegando por Autor "Baker, Glen B."
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Artigo Nitroprusside single-dose prevents the psychosis-like behavior induced by ketamine in rats for up to one week(Elsevier, 2015-03) Maia-de-Oliveira, Joao Paulo; Soares, Bruno Lobão; Ramalho, Thais; Gavioli, Elaine C.; Soares, Vanessa Paula; Teixeira, Leslie; Baker, Glen B.; Dursun, Serdar M.; Hallak, Jaime E.C.Recently, we found a rapid and long-lasting improvement of symptoms in schizophrenic patients on antipsychotics after a single four-hour infusion of sodium nitroprusside (SNP), a nitric oxide (NO) donor with a short half-life. This improvement persisted for up to 4 weeks. Because these patients remained on antipsychotics after infusion of SNP was finished, the question arises about whether this improvement was due to SNP itself. We have now investigated whether SNP, alone, can produce preventive antipsychotic effects in rats treated with ketamine (KET). 56 adult rats divided into 7 groups were infused with SNP 4 mg/kg, KET 25 mg/kg, or saline as follows: group1 — saline, group2 — SNP, group3 — KET, group4 — KET 12 h after SNP, group5 — KET 1 day after SNP, group6 — KET 2 days after SNP, and group7 — KET 1 week after SNP. The animals were filmed in an open field arena for 30 min and the videos were later analyzed by ANY-Maze software to measure activity and stereotypy. SNP significantly prevented the emergence of hyperactivity induced by KET when it was administered for up to 1 week before KET, and prevented the emergence of stereotypies when it was administered for up to 1 day before KET. These findings in rats, which have an even faster metabolic rate than humans, suggest that the long-lasting effects observed in our clinical trial with SNP in humans could have been due to SNP itself, and indicate for the first time that SNP may present preventive antipsychotic effects.Artigo Sodium nitroprusside, a nitric oxide donor for novel treatment of schizophrenia, may also modulate dopaminergic systems(Elsevier, 2014-11) Soares, Bruno Lobão; Maia-de-Oliveira, Joao Paulo; Baker, Glen B.; Hallak, Jaime E.C.; Dursun, Serdar M.“Schizophrenia is arguably the worst disease affecting mankind, even AIDS not excepted”. Since this statement in 1988 (Editors, 1988), schizophrenia still remains a major challenge to medicine, with up to 60% of patients not responding adequately to treatment despite the relatively large arsenal of antipsychotics currently available. By modulating the nitric oxide (NO) pathway, a new paradigm for schizophrenia treatment apparently involving modulation of nitric oxide (NO) has been proposed (Oliveira et al., 2011).Artigo Targeting the NMDA receptor-nitric oxide-cyclic GMP pathway to develop non-dopaminergic antipsychotic medications for schizophrenia(Associação Brasileira de Psiquiatria, 2011-09) Soares, Bruno Lobão; Oliveira, João Paulo Maia de; Machado-de-Sousa, João Paulo; Baker, Glen B.; Dursun, Serdar; Hallak, Jaime E. C.Schizophrenia is a devastating disorder that occurs in about 1% of the population worldwide. For over 30 years, it has been considered to be the result of dysfunctional brain dopaminergic pathways. However, dopaminergic antipsychotic drugs have proven effective for only some of the symptoms found in schizophrenia patients. Recent evidence suggests that dopaminergic abnormalities may be secondary to dysfunctions in multi-neurotransmitter systems modulating dopamine. One of the key neurotransmitters thought to be involved in schizophrenia is glutamate, and there is strong support for the involvement of a hypoactivity of N-methyl-D-aspartate (NMDA) glutamate receptors in the pathogenesis of schizophrenia. However, research with NMDA receptor agonists for the treatment of schizophrenia has produced inconsistent results, which may be due to the development of rapid tolerance to these compounds secondary to down-regulation of NMDA receptors. Perhaps the development of drugs that act on targets downstream NMDA receptors, such as nitric oxide (NO), could avoid the problem of the down-regulation of these receptors.