Asunto(s)
Corticosterona/metabolismo , Lóbulo Frontal/patología , Ácido Glutámico/metabolismo , Terminales Presinápticos/metabolismo , Estrés Psicológico/metabolismo , Estrés Psicológico/patología , Animales , Corticosterona/farmacología , Técnicas In Vitro , Terminales Presinápticos/efectos de los fármacosRESUMEN
Stress and glucocorticoids alter glutamatergic transmission, and the outcome of stress may range from plasticity enhancing effects to noxious, maladaptive changes. We have previously demonstrated that acute stress rapidly increases glutamate release in prefrontal and frontal cortex via glucocorticoid receptor and accumulation of presynaptic SNARE complex. Here we compared the ex vivo effects of acute stress on glutamate release with those of in vitro application of corticosterone, to analyze whether acute effect of stress on glutamatergic transmission is mediated by local synaptic action of corticosterone. We found that acute stress increases both the readily releasable pool (RRP) of vesicles and depolarization-evoked glutamate release, while application in vitro of corticosterone rapidly increases the RRP, an effect dependent on synaptic receptors for the hormone, but does not induce glutamate release for up to 20 min. These findings indicate that corticosterone mediates the enhancement of glutamate release induced by acute stress, and the rapid non-genomic action of the hormone is necessary but not sufficient for this effect.
Asunto(s)
Corticosterona/metabolismo , Lóbulo Frontal/patología , Neuronas/patología , Terminales Presinápticos/metabolismo , Estrés Psicológico/patología , Análisis de Varianza , Animales , Ácido Aspártico/metabolismo , Corticosterona/farmacología , Relación Dosis-Respuesta a Droga , Electrochoque/efectos adversos , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Técnicas In Vitro , Masculino , Neuronas/metabolismo , Terminales Presinápticos/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Estrés Psicológico/etiología , Sinapsinas/metabolismo , Vesículas Sinápticas/efectos de los fármacos , Vesículas Sinápticas/metabolismo , Sinaptosomas/metabolismo , Tritio/farmacocinéticaRESUMEN
Prompted by several cases of barium peritonitis of their own observation, the authors review the literature on the subject and outline the more common etiopathogenetic factors involved and gross and histological aspects of the disorders. After describing their own four cases of barium peritonitis, the authors outline some basic principles for the prevention and treatment of this rare complication.