Prostacyclin, indomethacin and the cerebral circulation.
The effect of intracarotid prostacyclin (PGI2) on cerebral blood flow (CBF) was measured by the 133xenon intracarotid injection technique in 8 baboons. Intracarotid prostacyclin increased CBF by 22% at 10(-7) g/kg/min and by 71% at 5 x 10(-6) g/kg/min, accompanied by systemic hypotension and tachycardia. The effects of PGI2 (10(-7) g/kg/min) were not potentiated by transient opening of the blood-brain barrier with the intracarotid hypertonic urea technique. At hypercapnia, the vasoconstrictor effect of indomethacin on the cerebral circulation was reversed by PGI2. These results support our suggestion that a prostaglandin, in particular PGI2, is required for hypercapnia to produce full cerebral vasodilatation. In separate experiments, following craniectomy in 5 cats, PGI2, but not its stable metabolite 6-keto-PGF1 alpha, dilated pial arterioles when locally injected into the mock CSF overlying the arteriole.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D002415:Cats; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D011464:Epoprostenol / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D007213:Indomethacin / Q000494:pharmacology*; D010100:Oxygen / Q000097:blood; D010215:Papio; D011453:Prostaglandins / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects
D011453:Prostaglandins; D002245:Carbon Dioxide; D011464:Epoprostenol; D010100:Oxygen; D007213:Indomethacin