title: Dual effect of prostaglandins on isolated intraocular porcine ciliary arteries.
abstract: OBJECTIVE
  Prostaglandin analogues are used to reduce the intraocular pressure (IOP) in glaucoma, but also affect the tone of the arteries supplying the ciliary body. Previously, the effect of prostaglandins has been studied on the extraocular ciliary arteries, whereas the effect on intraocular ciliary arteries has not been studied in detail.
  
  
  METHODS
  Intraocular long posterior porcine ciliary arteries were isolated and mounted in a myograph system for isometric tension recording, and the effects of PGF2α , the prostaglandin analogue latanoprost, PGD2 , PGE2 , PGI2 and the thromboxane analogue U46619 were studied in the presence and absence of selective receptor antagonists.
  
  
  RESULTS
  The prostaglandins PGD2 and PGE2 induced relaxation at low concentrations (10(-9) - 3 × 10(-7) m), which could be inhibited by blocking either the DP or the EP4 receptor, whereas PGD2 , PGE2 , PGF2α , latanoprost and U46619 induced contraction at high concentrations (10(-6) - 10(-5) m), which could be inhibited by blocking the TP receptor. Additionally, blocking of the FP receptor induced a right-shift of latanoprost-induced contraction.
  
  
  CONCLUSIONS
  Prostaglandins with affinity to DP1 and EP4 receptors induce relaxation at low concentrations, and prostaglandins with affinity to TP and FP receptors induce contraction at high concentrations of intraocular porcine ciliary vessels in vitro. The findings may contribute to understanding the regulation of blood flow to the ciliary body.
authors.affiliation: Department of Ophthalmology, Aarhus University Hospital, Aarhus C, Denmark. sidse@kringelholt.dk
authors.forename: Sidse
authors.initials: S
authors.lastname: Kringelholt
authors.forename: Ulf
authors.initials: U
authors.lastname: Simonsen
authors.forename: Toke
authors.initials: T
authors.lastname: Bek
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000818:Animals; D019842:Ciliary Arteries / Q000187:drug effects*; D002924:Ciliary Body / Q000098:blood supply*; D007052:Ibuprofen / Q000494:pharmacology; D007498:Iris / Q000098:blood supply; D007537:Isometric Contraction / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D009213:Myography; D010208:Papaverine / Q000494:pharmacology; D011453:Prostaglandins / Q000494:pharmacology*; D011982:Receptors, Prostaglandin / Q000819:agonists / Q000037:antagonists & inhibitors; D013552:Swine; D014661:Vasoconstriction / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology*
chemical_list: D011453:Prostaglandins; D011982:Receptors, Prostaglandin; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D010208:Papaverine; D007052:Ibuprofen