title: Electroretinogram responses of the normal thoroughbred horse sedated with detomidine hydrochloride.
abstract: OBJECTIVE
  The main objective was to record electroretinogram (ERG) parameters of normal thoroughbred mares using the HMsERG, a mini-Ganzfeld electroretinographic unit, and a contact lens electrode. The second objective was to determine whether IV detomidine hydrochloride at 0.015 mg/kg is consistently an effective choice for sedation of horses undergoing this ERG protocol.
  
  
  METHODS
  The study population consisted of 30 normal thoroughbred mares. ERG data were harvested using a protocol that included three different light intensities (10, 3000, and 10,000 mcd s/m(2)) and a 30-Hz flicker at 3000 mcd s/m(2).
  
  
  RESULTS
  Mean, median, standard deviation, and estimated normal ranges using the 5-95% of the data for a- and b-wave implicit times (IT), amplitudes (AMP), and b/a ratios were reported. Scotopic results at low intensity (10 mcd s/m(2)) had estimated ranges for b-wave IT of 41.8-72.9 ms and AMP of 19.8-173.3 μV. Middle intensity (3000 mcd s/m(2)) a-wave IT was 13.2-14.7 ms with a-wave AMP of 68.4-144 μV; the b-wave IT was 28.7-41.5 ms with b-wave AMP of 105.7-271.5 μV; and the b/a ratio was 0.95-2.71. The high-intensity (10,000 mcd s/m(2)) average recordings showed an a-wave IT of 13-14.9 ms, a-wave AMP of 85.7-186.8 μV; b-wave IT of 26.6-45.4 ms, b-wave AMP of 104.7-250.6 μV; and a b/a wave ratio of 0.7-2.0. The 30-Hz cone flicker showed an IT of 22.8-28.9 ms and AMP of 44.1-117.1 μV.
  
  
  CONCLUSIONS
  Results of normal thoroughbred ERG responses are reported. The protocol proved to be simple and safe and provided consistent results.
authors.affiliation: Eye Care for Animals, 13034 W Rancho Santa Fe Blvd, Suite 102, Avondale, AZ 85392, USA. mchurch@eyecareforanimals.com
authors.forename: Melanie L
authors.initials: ML
authors.lastname: Church
authors.forename: Joanna C
authors.initials: JC
authors.lastname: Norman
mesh_terms: D000818:Animals; D004596:Electroretinography / Q000662:veterinary*; D005260:Female; D006736:Horses / Q000502:physiology*; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology*; D012160:Retina / Q000502:physiology*
chemical_list: D006993:Hypnotics and Sedatives; D007093:Imidazoles; C041255:detomidine