In vitro application of endotoxin enhances nitric oxide production in thoracic aortas from Mg-deficient rats.
Since endotoxin-induced vascular hyporeactivity to phenylephrine is enhanced in Mg-deficient rats, this study was designed to determine whether endotoxin directly enhances nitric oxide (NO) production in thoracic aortas isolated from Mg-deficient rats in vitro. Thoracic aortas isolated from Mg-deficient and control rats were cultured for 6 h with or without endotoxin (LPS). LPS (0.01-1.0 microg) increased NO production in a concentration-dependent manner. NO production in the presence of 0.1 and 1.0 microg/mL LPS was significantly higher in Mg-deficient rat aortas compared to aortas from control rats. The enhanced NO production was not significantly affected by endothelium-denudation. LPS-stimulated NO production was fully inhibited by a selective iNOS inhibitor, 1400W (0.1, 1.0 microM), in control rat aortas, but in Mg-deficient rat aortas inhibition by 1400W was only partial. A similar inhibitory effect was observed with anti-CD14 and anti-TLR4 antibodies. These results suggest that endotoxin enhances NO production in Mg-deficient rat aortas directly, and that endotoxin receptors might, at least in part, contribute to this enhancement.
Miyamoto
A
A
Department of Veterinary Pharmacology, Faculty of Agriculture, Kagoshima University, Kagoshima, Japan.
Moriki
H
H
Ishiguro
S
S
Nishio
A
A
D000818:Animals; D000906:Antibodies / Q000378:metabolism; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism; D066298:In Vitro Techniques; D018950:Lipopolysaccharide Receptors / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008274:Magnesium / Q000378:metabolism*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D000906:Antibodies; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D009569:Nitric Oxide; D008274:Magnesium