Effects of endothelins (ET-1, ET-2 and ET-3) in the rabbit eye; role of prostaglandins.
The effects of intracameral injection of three endothelin isopeptides (ET-1, ET-2 and ET-3) were studied in the rabbit eye. All three peptides at pmol doses caused a dose-dependent rise in intraocular pressure (IOP) and an increase in protein concentration in the aqueous humor, indicating breakdown of the blood-aqueous barrier. Mean arterial blood pressure was not affected. ET-1 was more effective to increase IOP than were ET-2 and ET-3 whose effects seemed to be equal. ET-1 also caused vasodilation in the anterior uvea. The effects of ET-1, ET-2 and ET-3 on the IOP and blood-aqueous barrier, as well as the effects of ET-1 on regional blood flow in the eye, were abolished by pretreatment with indomethacin. Injection of 4 pmol ET-1 into the anterior chamber caused an increase in the concentration of prostaglandin E2 (PGE2) in the aqueous humor, most probably as a result of increased production of PGE2 in the anterior uvea. The results indicate that the effects of ET-1, ET-2 and ET-3 in the rabbit eye are to a large extent mediated by arachidonic acid metabolites.
Granstam
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E
Department of Physiology and Medical Biophysics, Uppsala University, Sweden.
Wang
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L
Bill
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A
D000818:Animals; D001082:Aqueous Humor / Q000187:drug effects / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D016232:Endothelins / Q000494:pharmacology*; D005123:Eye / Q000098:blood supply / Q000187:drug effects*; D005136:Eye Proteins / Q000378:metabolism; D005260:Female; D007213:Indomethacin / Q000494:pharmacology; D007429:Intraocular Pressure / Q000187:drug effects; D008297:Male; D011453:Prostaglandins / Q000502:physiology*; D011680:Pupil / Q000187:drug effects; D011817:Rabbits; D011863:Radioimmunoassay
D016232:Endothelins; D005136:Eye Proteins; D011453:Prostaglandins; D015232:Dinoprostone; D007213:Indomethacin