Effect of dexamethasone on nitric oxide (NO center dot) production by cultured astrocytes

Glial cell-derived nitric oxide (NO .) and its regulation has significant i mplications for central nervous system pathophysiology. The aim of the pres ent study was to determine the production of NO . by cultured rat astrocyte s and peritoneal macrophages, and its regulation by glucocorticoids. Result s corroborate the presence of both constitutive and induced NO . synthase ( cNOS and iNOS) in astrocytes, while macrophages express only the inducible isoform. Dexamethasone was able to decrease NO . synthesis produced by indu ction of iNOS in macrophage and astrocyte phagocytosis, but not the NO . pr oduced by the cNOS spontaneously expressed in cultured astrocytes.