Biomedical subjects
Publications and source records attributed to G W van Alphen.
The adrenergic receptors in man were analyzed using isolated sphincter, dilator, and ciliary muscle strips, dissected from eyebank eyes. The dilator is mainly alpha, the sphincter both alpha and beta, and the ciliary muscle predominantly beta adrenergic.
Both sphincter and dilator muscle preparations of the cat iris contract to prostaglandins; F-2alpha and E-2 are the most potent and A-1 and B-1 the least. Ciliary muscle strips relax to PG'S provided that the strips are precontracted. E-1, E-2 and often F-2alpha 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.