Nitric oxide changes in the rat brain after transient middle cerebral artery occlusion.
Using a porphyritic microsensor, we measured the cortical NO concentration within ischemic tissue during 2 h of middle cerebral artery (MCA) occlusion and 1 h of reperfusion in the rat (n = 36). Local cerebral blood flow was simultaneously measured by laser Doppler flowmetry to verify MCA occlusion and reperfusion. Baseline concentration of NO was < 10(-8) M. The maximum concentrations of NO during MCA occlusion and reperfusion were, respectively, 1.47 +/- 0.45 microM and 0.54 +/- 0.24 microM. Administration of N-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthase, prior to ischemia, significantly (p < 0.05) reduced NO release to 0.04 +/- 0.02 microM during MCA occlusion and completely inhibited NO release during 1 h of reperfusion. Administration of L-arginine 30 min after administration of L-NAME restored NO release (3.45 +/- 1.14 microM) during MCA occlusion; however, administration of L-arginine did not overcome the effect of L-NAME on mean arterial blood pressure. Our data indicate that NO is released in the brain after the onset of ischemia and NO levels can be modulated by administration of NO substrate and NO antagonists.
Zhang
Z G
ZG
Department of Neurology, Henry Ford Health Science System, Detroit, MI 48202-2689, USA.
Chopp
M
M
Bailey
F
F
Malinski
T
T
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000187:drug effects; D001923:Brain Chemistry / Q000502:physiology*; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D002536:Cerebral Arteries / Q000502:physiology*; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D006651:Histocytochemistry; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology
D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D019331:NG-Nitroarginine Methyl Ester