Role of L-arginine-derived nitric oxide in cholinergic dilation of gastric arterioles.
The role of L-arginine-derived nitric oxide (NO) in cholinergic vasodilation of resistance vessels was studied in the intact stomach of the rat, utilizing an in vivo microscopy technique. Two L-arginine analogues, NG-monomethyl-L-arginine (L-NMMA) and nitro-L-arginine methyl ester (L-NAME), were used to block NO synthesis. Cholinergic dilation of gastric submucosal arterioles was induced by topical application of various concentrations of acetylcholine (ACh) (10(-7)-10(-4) M). Intravenous but not topical administration of L-NMMA and L-NAME caused an increase in arterial pressure. Intravenous or topical L-NAME reduces resting arteriolar diameter. These findings support the contention that NO formation modulates basal vascular tone and suggest that NO release may play a significant role in the regulation of the gastric circulation. L-Arginine analogues attenuated the arteriolar dilating effect of ACh but not adenosine or nitroglycerin. Substantial arteriolar responses to ACh remained after systemic or topical treatment with either L-NMMA or L-NAME. These results indicate that the L-arginine-NO pathway accounts only in part for ACh-induced vasodilation in gastric resistance vessels in vivo.
Chen
R Y
RY
Anesthesiology Service, Veterans Affairs Medical Center West Los Angeles, California.
Ross
G
G
Chyu
K Y
KY
Guth
P H
PH
D000109:Acetylcholine / Q000494:pharmacology*; D000287:Administration, Topical; D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D001160:Arterioles / Q000187:drug effects; D007275:Injections, Intravenous; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013270:Stomach / Q000098:blood supply; D014664:Vasodilation / Q000502:physiology*; D019323:omega-N-Methylarginine
D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester