Cerebral vasodilation and prostacyclin. The effects of aspirin and meclofenamate in vitro.

The effects of aspirin and meclofenamic acid on the diphasic responses produced by prostacyclin in isolated canine basilar arteries were compared. Meclofenamate enhanced the relaxant action of prostacyclin in low concentrations (10(-8)M to 10(-6)M) and also significantly inhibited the contractions caused by the highest concentration (10(-5)M) of this prostaglandin. Aspirin had no such effects. The results indicate that some drugs classified as prostaglandin synthetase inhibitors can directly enhance the vasodilator action of prostacyclin on cerebral arteries, and suggest that this enhancement could be of value in the clinical applications of prostacyclin.