The second messenger of sphingomyelin signaling, ceramide, acts as an intracellular signal via phosphatase activation and protein kinase C (PKC) inhibition. We tested the hypothesis that ceramide may have an regulatory role in determining vascular tone. Natural ceramide was applied to phenylephrine precontracted aortic rings from Sprague-Dawley rats in an organ bath. In endothelium-intact aortic rings, concentration of ceramide at 10 - 6 and 10 -5 mole/L induced 24 ± 6 and 52 ± 7% relaxation, respectively. Removal of the endothelium significantly inhibited ceramide-induced relaxation to 13 ± 5% (10 -6 mole/L) and 29 ± 5% (10 -5 mole/L). Similar inhibition was observed in endothelium-intact aortic rings pretreated with N(ω)-nitro-L-arginine (10 -4 mole/L) or methylene blue (10 -5 mole/L), suggesting that endothelium-derived nitric oxide is involved in ceramide- induced relaxation. N-acetylsphingosine (C 2 -ceramide), N-hexanoylsphingosine (C 6 -ceramide), N-palmitoylsphingosine (C 16 -ceramide) and D-sphingosine all demonstrated dose-dependent relaxation responses in endothelium-intact vessels. Sphingomyelin signaling through the nitric oxide-dependent mechanism may have an important role in regulating vascular tone.
|Original language||English (US)|
|Number of pages||5|
|Journal||Chinese Journal of Physiology|
|State||Published - Jan 1 1999|
- Vascular smooth muscles
ASJC Scopus subject areas
- Physiology (medical)