title: Pharmacological effects of latanoprost, prostaglandin E2, and F2alpha on isolated rabbit ciliary artery.
abstract: BACKGROUND
  Latanoprost is a prostaglandin (PG)F2alpha analogue widely recognized in the treatment of glaucoma. To investigate the action of this drug on the ocular circulation, we have studied its effects on isolated rabbit ciliary artery. The data obtained on this drug are compared with the data from PGE2 and PGF2alpha.
  
  
  METHODS
  Under the microscope, ciliary artery specimens were prepared from rabbit eyes and mounted in a myograph system. The effects of latanoprost, PGE2, and PGF2alpha on the isolated rabbit ciliary artery were investigated in vitro using isometric tension recording methods.
  
  
  RESULTS
  Exogenously applied PGF2alpha, but not latanoprost, evoked contraction in the rabbit ciliary artery. After precontraction with excess-[K]0 solution, latanoprost evoked relaxation dose-dependently. Latanoprost at a concentration of 100 microM induced maximum relaxation, which was not blocked by 10 microM L-nitro-L-arginine methylester (L-NAME), 1 microM 8-37 calcitonin gene-related peptide (CGRP) or 10 microM indomethacin. Moreover, latanoprost induced relaxation even in preparations without endothelium. The maximum relaxation obtained with PGE2 was somewhat less than 50% of that with latanoprost.
  
  
  CONCLUSIONS
  These results indicate that latanoprost and PGE2 relaxed rabbit ciliary artery to different degrees. The relaxation provoked by latanoprost was not dependent on endothelium and was not caused by intrinsic PG, CGRP or nitric oxide. The mechanism of this relaxation is not yet clear.
authors.affiliation: Department of Ophthalmology, Kitasato University, Sagamihara, Japan. hitoshi@cx.airnet.ne.jp
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshitomi
authors.forename: Kimiyo
authors.initials: K
authors.lastname: Mashimo
authors.forename: Motoi
authors.initials: M
authors.lastname: Nakanishi
authors.forename: Kimiya
authors.initials: K
authors.lastname: Shimizu
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D019842:Ciliary Arteries / Q000187:drug effects*; D015237:Dinoprost / Q000494:pharmacology*; D015232:Dinoprostone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004576:Electromyography; D007213:Indomethacin / Q000494:pharmacology; D007537:Isometric Contraction / Q000502:physiology; D000077338:Latanoprost; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D011461:Prostaglandins F, Synthetic / Q000494:pharmacology*; D011817:Rabbits; D014661:Vasoconstriction / Q000502:physiology; D014664:Vasodilation / Q000502:physiology*
chemical_list: D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost; D015237:Dinoprost; D015740:Calcitonin Gene-Related Peptide; D015232:Dinoprostone; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin