Responses of the cerebral blood flow to hypo-and hypercapnia after inhibition of prostaglandin biosynthesis by indomethacin

Quantitative investigation of the local cerebral blood flow by the hydrogen clearance method and of the blood flow into the brain by means of an electromagnetic flowmeter showed that inhibition of prostaglandin biosynthesis by indomethacin inhibits the response of the cerebral vessels to hypercapnia, whereas the effects of hypocapnia are not only preserved but are actually enhanced. This difference in the response of the brain vessels to hypo- and hypercapnia during inhibition of prostaglandin biosynthesis suggests that effects of hyper- and hypocapnia are produced by different mechanisms. It is postulated that a decrease in the prostaglandin concentration reduces the sensitivity of the brain vessels to hypercapnia and increases their sensitivity to hypocapnia.Problem Laboratory for Pharmacology of the Cardiovascular System, Department of Pharmacology, Erevan Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 3, pp. 240–243, March, 1979.