Mechanism of hypoxia-induced alteration in cerebral arteriolar tone in rats.
We studied the changes in pial arteriolar diameter during hypoxia and 60 and 120 min after restoration of normoxia, using the closed cranial window technique in artificially ventilated and normocapnic rats. Pial arteriolar diameter increased 16 +/- 4% during hypoxia (PaO2 less than 25 mm Hg, lasting 10 min). Although blood pressure (BP), heart rate (HR), and blood gases returned to prehypoxic level when measured at 60 and 120 min after hypoxia, pial arterial diameter decreased significantly (13 +/- 5 and 16 +/- 6% below control levels, respectively). This posthypoxic vasoconstriction was reversed by treatment of the brain surface with L-660,711 (10(-5) M), a specific leukotriene D4 receptor antagonist. These data suggest that leukotrienes may be involved in delayed cerebral vasoconstriction that follows a brief period of hypoxia.
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Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Sharma
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Ong
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Bose
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D000818:Animals; D001160:Arterioles / Q000503:physiopathology*; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000187:drug effects; D002536:Cerebral Arteries / Q000503:physiopathology*; D006321:Heart / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D009129:Muscle Tonus / Q000502:physiology*; D011422:Propionates / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013189:SRS-A / Q000037:antagonists & inhibitors / Q000494:pharmacology; D014661:Vasoconstriction / Q000502:physiology
D011422:Propionates; D011804:Quinolines; D013189:SRS-A; C059141:verlukast