The mechanism by which mechanical stress induces nitric oxide (NO) synthesi
s in endothelium is still controversial. Hypotonic stress (HTS, -20%) induc
ed ATP release, which evoked Ca2+ transients in bovine aortic endothelial c
ells (BAEC), HTS also induced NO synthesis, assessed by DAF-S fluorescence,
which was suppressed by inhibiting endogenous ATP-induced Ca2+ transients
with suramin or neomycin, Exogenously applied ATP mimicked these responses.
Pretreatment with wortmannin did not affect DAF-2 fluorescence, suggesting
that Akt phosphorylation was not involved in MTS-induced NO synthesis, The
se results indicate that endogenous ATP plays a central role in HTS-induced
NO synthesis in BAEC. (C) 2000 Academic Press.