Investigations of the function of the vascular endothelium in portal hypertensive rats.
There were no differences between mesenteric arteries from sham or 14-day portal hypertensive (PH) rats in the potency of or maximum endothelium-dependent relaxations (EDR) to acetylcholine. There were no differences between sham-operated and PH rats in the effects of the combination of the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (100 mumol/l) and methylene blue (10 mumol/l) in causing a significant reduction in the EDR to acetylcholine. The degree of portal-systemic shunting, as measured by 57Co-labeled microspheres, was unaffected by acute administration of NG-monomethyl-L-arginine (50 mg/kg) or methylene blue (5 mg/kg). In conclusion, nitric oxide is the main mediator of EDR in rat mesenteric artery, and no evidence was found for an increased role for endothelial-derived nitric oxide in PH rats.
Cawley
T
T
Department of Physiology, Royal College of Surgeons, Ireland, Dublin.
Breslin
E
E
Geraghty
J
J
Osborne
H
H
Docherty
J R
JR
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000109:Acetylcholine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D004396:Coloring Agents; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000378:metabolism / Q000502:physiology*; D006975:Hypertension, Portal / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000378:metabolism; D008751:Methylene Blue / Q000494:pharmacology; D008863:Microspheres; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013928:Thromboxane A2 / Q000031:analogs & derivatives / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D019323:omega-N-Methylarginine / Q000494:pharmacology*
D004396:Coloring Agents; D011450:Prostaglandin Endoperoxides, Synthetic; D014662:Vasoconstrictor Agents; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D013928:Thromboxane A2; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D019001:Nitric Oxide Synthase; D000109:Acetylcholine; D008751:Methylene Blue