Decreased vasoconstrictor responses in remote cerebral arteries after focal brain ischemia and reperfusion in the rat, in vitro.
The effects of brain ischemia and reperfusion on smooth muscle function in remote cerebral and peripheral arteries are hardly known. Maximum vasoconstrictions (E(max)) caused by 120mmol/l KCl and 5-HT in endothelium-denuded ring preparations were measured in ischemic and control cerebral arteries of rats after a 1-h right middle cerebral artery occlusion followed by 0-min (I/NR) or 2-3-min (I/SR) reperfusion, and in peripheral arteries after I/SR. Surprisingly, vasoconstrictions to 5-HT and 120mmol/lK(+) were attenuated in remote brain vessels after I/SR, i.e. in the contralateral middle cerebral artery and the basilar artery, while I/NR depressed E(max) of 5-HT and high KCl only in the ischemic middle cerebral artery. Pretreatment with N-(2-mercaptopropionyl) glycine (MPG, 100mg/kg i.p.), a free radical scavenger, fully prevented the impairment of vasomotor function in the middle cerebral artery on both sides after I/SR. Moreover, vasomotor functions were normal in the coronary, renal and pulmonary arteries after I/SR. In conclusion, focal cerebral ischemia and reperfusion impaired vasoconstrictor responses in remote brain arteries of rats by a mechanism involving free radicals. The lack of similar effects in peripheral vessels indicates poor defence of brain arteries against remote injury caused by reactive oxygen species-dependent mechanisms.
Kovács
Anikó
A
EGIS Pharmaceuticals PLC, Division of Preclinical Research, 1106 Keresztúri út 30-38, Budapest, Hungary.
Móricz
Krisztina
K
Albert
Mihály
M
Benedek
Angéla
A
Hársing
László G
LG
Szénási
Gábor
G
D000818:Animals; D002545:Brain Ischemia / Q000209:etiology / Q000503:physiopathology*; D002536:Cerebral Arteries / Q000503:physiopathology; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D020244:Infarction, Middle Cerebral Artery / Q000150:complications; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000503:physiopathology; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000150:complications; D012701:Serotonin / Q000494:pharmacology; D013438:Sulfhydryl Compounds / Q000494:pharmacology*; D013997:Time Factors; D014661:Vasoconstriction / Q000187:drug effects*
D016166:Free Radical Scavengers; C110658:N-(2-mercaptoproprionyl)-glycine; D013438:Sulfhydryl Compounds; D012701:Serotonin; D011189:Potassium Chloride; D005998:Glycine