L-arginine dilates rat pial arterioles by nitric oxide-dependent mechanisms and increases blood flow during focal cerebral ischaemia.
L-Arginine (> or = 30 mg kg-1, i.v.), but not D-arginine (300 mg kg-1) administered 5 min after unilateral common carotid/middle cerebral artery occlusion increased regional cerebral blood flow (rCBF) within the dorsolateral ischaemic cortex in spontaneously hypertensive rats. L-Arginine (300 mg kg-1) increased rCBF from 22 +/- 2.7 to 33 +/- 4% of baseline as measured by laser-Doppler flowmetry. This increase may explain the ability of L-arginine to reduce infarct size following focal cerebral ischaemia, as reported previously. The mechanism appears to be mediated by nitric oxide since topical L-NAME (1 microM), a nitric oxide synthase inhibitor, decreased pial arteriole calibre from 115 +/- 2.2 to 106 +/- 0.9% of baseline following L-arginine infusion (300 mg kg-1).
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology*; D001160:Arterioles / Q000187:drug effects; D002545:Brain Ischemia / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase; D010841:Pia Mater / Q000098:blood supply*; D051381:Rats; D011918:Rats, Inbred SHR; D017207:Rats, Sprague-Dawley; D013237:Stereoisomerism; D014664:Vasodilation / Q000187:drug effects*
D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D019331:NG-Nitroarginine Methyl Ester