title: Evaluation of the effects of tricaine methanesulfonate on retinal structure and function in koi carp (Cyprinus carpio).
abstract: OBJECTIVE
  To determine whether repeated exposure to clinically relevant concentrations of tricaine methanesulfonate (MS-222) would alter retinal function or induce histologically detectable retinal lesions in koi carp (Cyprinus carpio).
  
  
  METHODS
  Prospective, controlled, experimental study.
  
  
  METHODS
  18 healthy koi carp.
  
  
  METHODS
  2 fish were euthanized at the start of the study, and eyes were submitted for histologic evaluation as untreated controls. Anesthesia was induced in the remaining fish with 200 mg of MS-222/L and maintained with concentrations of 125 to 150 mg/L for a total exposure time of 20 minutes daily on 1 to 13 consecutive days. On days 1, 7, and 13, electroretinography of both eyes was performed in all fish remaining in the study, and 2 fish were euthanized immediately after each procedure for histologic evaluation of the eyes. Median b-wave amplitudes were compared among study days for right eyes and for left eyes via 1-way repeated-measures ANOVA with a Bonferroni correction for multiple comparisons.
  
  
  RESULTS
  Median b-wave amplitudes on days 1, 7, and 13 were 17.7, 20.9, and 17.6 μV, respectively, for right eyes and 15.1, 16.9, and 14.3 μV, respectively, for left eyes. No significant differences in b-wave amplitudes were detected among study days. No histopathologic abnormalities were identified in the retinas of any fish treated with MS-222 or in control fish.
  
  
  CONCLUSIONS
  Short-term exposure of koi carp to clinically relevant concentrations of MS-222 daily for up to 13 days was not associated with changes in retinal structure or function as measured in this study.
authors.affiliation: Department of Molecular and Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA. kate_bailey@ncsu.edu
authors.forename: Kate M
authors.initials: KM
authors.lastname: Bailey
authors.forename: Julie E
authors.initials: JE
authors.lastname: Hempstead
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Tobias
authors.forename: Luke B
authors.initials: LB
authors.lastname: Borst
authors.forename: Alison B
authors.initials: AB
authors.lastname: Clode
authors.forename: Lysa P
authors.initials: LP
authors.lastname: Posner
mesh_terms: D062365:Aminobenzoates / Q000009:adverse effects* / Q000494:pharmacology; D000777:Anesthetics / Q000009:adverse effects* / Q000494:pharmacology; D000818:Animals; D002347:Carps; D005393:Fish Diseases / Q000139:chemically induced*; D012164:Retinal Diseases / Q000139:chemically induced / Q000662:veterinary*
chemical_list: D062365:Aminobenzoates; D000777:Anesthetics; C003636:tricaine