Altered antioxidant status has been implicated in schizophrenia. Microglia, major sources of free radicals such as superoxide (O2-), play crucial roles in various brain pathologies. Recent postmortem and imaging studies have indicated microglial activation in the brain of schizophrenic patients. We previously demonstrated that atypical antipsychotics including aripiprazole significantly inhibited the release of nitric oxide and proinflammatory cytokines from interferon-γ-stimulated microglia in vitro. Antioxidative effects of antipsychotics via modulating microglial superoxide generation have never been reported. Therefore, we herein investigated the effects of antipsychotics on the O2- generation from phorbol-myristate-acetate (PMA)-stimulated rodent microglia by the electron spin resonance (ESR) spectroscopy and also examined the intracellular mechanism by intracellular Ca2+ imaging and immunostaining. Neuronal damage induced by microglial activation was also investigated by the co-culture experiment.Among various antipsychotics, only aripiprazole inhibited the O2- generation from PMA-stimulated microglia. Aripiprazole proved to inhibit the O2- generation through the cascade of protein kinase C (PKC) activation, intracellular Ca2+ regulation and NADPH oxidase activation via cytosolic p47phox translocation to the plasma/phagosomal membranes. Formation of neuritic beading, induced by PMA-stimulated microglia, was attenuated by pretreatment of aripiprazole.D2R antagonism has long been considered as the primary therapeutic action for schizophrenia. Aripiprazole with D2R partial agonism is effective like other antipsychotics with fewer side effects, while aripiprazole's therapeutic mechanism itself remains unclear. Our results imply that aripiprazole may have psychotropic effects by reducing the microglial oxidative reactions and following neuronal reactions, which puts forward a novel therapeutic hypothesis in schizophrenia research.
All Science Journal Classification (ASJC) codes
- Psychiatry and Mental health
- Biological Psychiatry