Nitric oxide production in living neurons is modulated by sphingosine: a fluorescence microscopy study

An investigation was carried out into the possible effect of sphingosine (S ph) on nitric oxide (NO) production in living neurons. Differentiated granu le cells were used in a dynamic videoimaging analysis of single cells label ed, simultaneously, with FURA-2 and the NO indicator 4,5-diaminofluorescein . The results demonstrate that Sph exerts a potent inhibitory effect on the Ca2+-dependent production of NO, without modifying the [Ca2+](i). The effe ct appears to be specific as neither ceramide nor Sph-l-phosphate had any e ffect on the NO and [Ca2+](i) levels. The data demonstrate that Ca2+-depend ent NO production is a specific Sph target in living granule cells, suggest ing that this bioactive sphingoid plays a relevant role in neuronal NO sign aling. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.