title: An endothelin-1-induced model of chronic optic nerve ischemia in rhesus monkeys.
abstract: OBJECTIVE
  The purpose of this study was to evaluate flow reduction to the optic nerve after chronic administration of endothelin-1 in primates.
  
  
  METHODS
  Endothelin-1 (three rhesus monkeys), in a dosage of 0.1 microgram/day, or balanced salt solution (three rhesus monkeys) was delivered to the perineural region of the anterior optic nerve via osmotically driven minipumps. Optic nerve blood flow was determined by means of a colored microspheres technique after 7 days of local endothelin-1 or balanced salt solution administration. The effect of endothelin-1 on optic nerve blood flow was analyzed by analysis of convariance (ANCOVA) in a 2 (between groups: endothelin-1, balanced salt solution) x 2 (within subject: blood flow minipump optic nerve, blood flow controls) design, with intraocular pressure as a changing covariate.
  
  
  RESULTS
  The decrease of optic nerve blood flow in the endothelin-1 eyes was significant compared to the balanced salt solution eyes (ANCOVA p = 0.015). Among the monkeys implanted with endothelin-1 minipumps, the decrease in optic nerve blood flow in the experimental eye compared to the contralateral eye (mean +/- SD 35.7 +/- 9.1%) was significant (p = 0.01), while that among the monkeys implanted with balanced salt solution minipumps (mean +/- SD 0.7 +/- 5.5%) was not (p = 0.73).
  
  
  CONCLUSIONS
  This new primate model of chronic optic nerve ischemia may represent a method to evaluate experimentally the implication of a local hemodynamic perturbation in various optic neuropathies.
authors.affiliation: Devers Eye Institute, Legacy Portland Hospitals, Oregon, USA.
authors.forename: S
authors.initials: S
authors.lastname: Orgül
authors.forename: G A
authors.initials: GA
authors.lastname: Cioffi
authors.forename: D R
authors.initials: DR
authors.lastname: Bacon
authors.forename: E M
authors.initials: EM
authors.lastname: Van Buskirk
mesh_terms: D000818:Animals; D002908:Chronic Disease; D019332:Endothelin-1 / Q000008:administration & dosage; D007429:Intraocular Pressure; D007511:Ischemia / Q000139:chemically induced / Q000503:physiopathology*; D008253:Macaca mulatta; D008863:Microspheres; D009900:Optic Nerve / Q000098:blood supply*; D012039:Regional Blood Flow / Q000187:drug effects
chemical_list: D019332:Endothelin-1