NITRIC-OXIDE MEDIATES NMDA-EVOKED [H-3] GABA RELEASE FROM CHICK RETINA CELLS

The stimulation of NMDA receptor increased [H-3]GABA release from prel oaded cultured retina cells. This effect appears to be mediated by NO production, since addition of L-NA reduces NMDA-evoked [H-3]GABA relea se. Spermine/ NO complex, an NO donor, mimics the effect produced by N MDA, The addition of zaprinast, a phosphodiesterase inhibitor, as well as 8-Br-cGMP enhances the NMDA-evoked [H-3]GABA release. These result s agree with the existence in chick retina cells of NO/cGMP pathways a nd support a role for NO in NMDA-evoked events, The activation of this receptor complex through maturative stages of the retina together wit h the NO-mediated increase in GABA release may account for NMDA differ entiative effect in culturing retina cells. (C) 1997 Federation of Eur opean Biochemical Societies.