RESUMEN
Variations in anxiety-related behavior are associated with individual allostatic set-points in chronically stressed rats. Actively offensive rats with the externalizing indicators of sniffling and climbing the stimulus and material tearing during 10 days of predator scent stress had reduced plasma corticosterone, increased striatal glutamate metabolites, and increased adrenal 11-dehydrocorticosterone content compared to passively defensive rats with the internalizing indicators of freezing and grooming, as well as to controls without any behavioral changes. These findings suggest that rats that display active offensive activity in response to stress develop anxiety associated with decreased allostatic set-points and increased resistance to stress.
Asunto(s)
Ansiedad/metabolismo , Ansiedad/psicología , Cuerpo Estriado/metabolismo , Ácido Glutámico/metabolismo , Hipotálamo/metabolismo , Sistema Límbico/metabolismo , Sistema Hipófiso-Suprarrenal/metabolismo , Estrés Psicológico , Animales , Ansiedad/diagnóstico por imagen , Ansiedad/etiología , Conducta Animal , Biomarcadores , Cuerpo Estriado/fisiopatología , Modelos Animales de Enfermedad , Hormonas/metabolismo , Imagen por Resonancia Magnética , Masculino , Aprendizaje por Laberinto , Ratas , Análisis Espectral , Estrés FisiológicoRESUMEN
Methods for growing primary neuronal cultures rely on the inclusion of antioxidants in the culture medium, but no studies have determined precisely if or when antioxidants are required for neuronal survival, despite the significance this information would have for understanding neurodevelopment and studying oxidative stress. We show that cortical neurons grown in Neurobasal media with B27 supplement required antioxidants for only the first 24 hr post-explantation, after which the antioxidants could be removed permanently without noticeable loss of neuronal survival over the normal lifespan. Cortical cultures never exposed to antioxidants did not survive. These findings represent a novel method for substantially antioxidant-free neuronal culture, whereby antioxidants can be removed permanently from the cultures after only 1 day. This method may prove critical for studies of oxidative stress, because B27 antioxidants significantly diminished pro-oxidative effects of the excitatory neurotransmitter glutamate and hydrogen peroxide on cortical cultures, even if antioxidants were removed before the oxidizing treatment. Together, these findings suggest a brief window of high vulnerability to reactive oxygen species, and have important implications for studies of oxidative stress and developmental neuroscience.