Effects of prostaglandins on the cerebral circulation in the coat.

The role of prostaglandins in producing cerebrovasodilation during hypercapnia was tested in goats. Cerebral blood flow (CBF) changes with increasing arterial PCO2 were measured before and after prostaglandin synthesis inhibition with indomethacin or ibuprofen. Both drugs produced significant decreases in CBF under control anesthetized conditions but had no significant effect on the cerebrovascular response to increased arterial PCO2. The effects of direct intracerebrovascular infusion of prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha) and prostacyclin were also measured. In the dose range tested (0.1-1) microgram/min) PGF2 alpha had no significantly greater than that produced by PGE2. The effectiveness of each compound in producing cerebrovascular changes is consistent with the endogenous distribution of prostaglandins within the brain. These results suggest that prostaglandins, particularly PGI2, may be important in modulating cerebrovascular tone but have no role in increasing CBF during hypercapnia.