Activity of prostaglandin E, F, A and B on sphincter, dilator and ciliary muscle preparations of the cat eye

Abstract

Both sphincter and dilator muscle preparations of the cat iris contract to prostaglandins; F2[alpha] and E2 are the most potent and A1 and B1 the least. Ciliary muscle strips relax to PG's provided that the strips are precontracted. E1, E2 and often F2[alpha] are more potent relaxants than the remaining PG's. The effects of PG's are not altered by [alpha] or [beta] blockade nor by atropine; however, propranolol blocks the PG induced relaxation of the ciliary muscle. The effects of PG's on the sphincter are antagonized by catecholamines; but the latter act synergistically in contracting the dilator and in relaxing the ciliary muscle. Indomethacin markedly potentiates the effects of PG's on all three muscle preparations.