Nitric oxide is the endothelium-derived relaxing factor in bovine pial arterioles.
The purpose of this study was to investigate the formation and action of a nitric oxide-related endothelium-derived relaxing factor in cerebral arteries of cattle. Pial artery segments (0.6-1 mm o.d.) were incubated in oxygenated (20%) Krebs-Henseleit buffer containing indomethacin. Addition of acetylcholine (0.1 microM) to rings precontracted by serotonin (0.1 microM) resulted in a significant (p less than 0.05) relaxation. This response disappeared after removal of the endothelium and addition of hemoglobin, a nitric oxide scavenger, and NG-monomethyl-L-arginine, an inhibitor of L-arginine-derived nitric oxide biosynthesis. L-Arginine (10 microM) considerably attenuated the inhibitory action of NG-monomethyl-L-arginine. Relaxations induced by 3-morpholinosydnonimine and nitroglycerin (0.1 microM), two exogenous sources of nitric oxide, were unaffected by NG-monomethyl-L-arginine (10 microM) but abolished by hemoglobin. These data strongly suggest nitric oxide as the mediator of endothelium-derived relaxation in pial arteries of the cattle.
Fischer-Nakielski
H
H
Institut für Pharmakologie, Heinrich-Heine-Universität Düseldorf, FRG.
Schrör
K
K
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001160:Arterioles / Q000378:metabolism; D002417:Cattle; D004730:Endothelium, Vascular / Q000502:physiology; D006454:Hemoglobins / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism*; D005996:Nitroglycerin / Q000494:pharmacology; D010841:Pia Mater / Q000098:blood supply*; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects; D019323:omega-N-Methylarginine
D006454:Hemoglobins; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine; D005996:Nitroglycerin; D000109:Acetylcholine