[The role of prostaglandins in the regulation of retinal blood flow].

Hypercapnia causes vasodilatation of retinal arterioles. Prostaglandin E1, injected close to retinal arterioles from the vitreal side cause vasodilatation apparently similar to that caused by hypercapnia. An inhibitor of prostaglandin synthase (indomethacin) was injected into the ocular circulation. There was a reversible inhibition of the retinal vasodilatation normally induced by hypercapnia. Indomethacin injected close to retinal arterioles from the vitreal side causes reversible vasoconstriction and inhibits the vasodilatory effect of hypercapnia. It is concluded that prostaglandin E1 satisfies three criteria for a candidate for a mediator of hypercapnia-induced arteriolar dilatation.