title: Effects of aspirin and indomethacin on cerebral circulation in the conscious rat: evidence for a physiological role of endogenous prostaglandins.
abstract: The purpose of this work was to evaluate the effects of equipotent doses of two different inhibitors of cyclo-oxygenase, indomethacin and aspirin, on cerebral blood flow and cerebral vascular resistances in the conscious undisturbed rat, using the reference sample radioactive microsphere method. We found that both, aspirin (50 mg/kg) and indomethacin (5 mg/kg) at 3, 15 and 60 min after their intravenous administration, increased cerebral vascular resistances and decreased cerebral blood flow to a similar extent. Both drugs completely abolished the hypotensive effect of 5 mg/kg i.v. arachidonic acid and they did not change arterial PO2, PCO2 or pH values. We conclude that the pharmacological inhibition of cyclooxygenase in the conscious undisturbed rat leads to a cerebral vasoconstriction and consequently to a decrease in cerebral blood flow. Our results evidence that prostaglandins are a physiological factor that actively contributes to the maintenance of cerebral circulation.
mesh_terms: D000818:Animals; D001241:Aspirin / Q000494:pharmacology*; D001921:Brain / Q000098:blood supply; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D003243:Consciousness / Q000502:physiology; D007213:Indomethacin / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D011453:Prostaglandins / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D011453:Prostaglandins; D001241:Aspirin; D007213:Indomethacin