Nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) e
xerts inhibitory and cytotoxic effects on various cells including neur
onal cells. In the present study, we examined the ability of rat glial
cells to produce NO following hypoxia/reoxygenation in vitro by measu
ring nitrite. The levels of nitrite produced in the cultured media of
glial cells significantly increased after 12-h hypoxia but not after 0
- and 6-h hypoxia. The NOS inhibitor, N-G-monomethyl-L-arginine, decre
ased hypoxia-induced nitrite formation. In glial cells after hypoxia/r
eoxygenation, the iNOS mRNA and protein expressions were detected by r
everse-transcription polymerase chain reaction and by immunocytochemic
al analysis, respectively. The present study provides the first eviden
ce that hypoxia induces NO production from glial cells. This hypoxia-i
nduced, glial cell-derived NO may play a critical role in the pathogen
esis of cerebral ischemia in vivo.