title: Pigmented and albino rats differ in their responses to moderate, acute and reversible intraocular pressure elevation.
abstract: To compare the electrophysiological and morphological responses to acute, moderately elevated intraocular pressure (IOP) in Sprague-Dawley (SD), Long-Evans (LE) and Brown Norway (BN) rat eyes.
  
  
  
  Eleven-week-old SD (n = 5), LE (n = 5) and BN (n = 5) rats were used. Scotopic threshold responses (STRs), Maxwellian flash electroretinograms (ERGs) or ultrahigh-resolution optical coherence tomography (UHR-OCT) images of the rat retinas were collected from both eyes before, during and after IOP elevation of one eye. IOP was raised to ~35 mmHg for 1 h using a vascular loop, while the other eye served as a control. STRs, ERGs and UHR-OCT images were acquired on 3 days separated by 1 day of no experimental manipulation.
  
  
  
  There were no significant differences between species in baseline electroretinography. However, during IOP elevation, peak positive STR amplitudes in LE (mean ± standard deviation 259 ± 124 µV) and BN (228 ± 96 µV) rats were about fourfold higher than those in SD rats (56 ± 46 µV) rats (p = 0.0002 for both). Similarly, during elevated IOP, ERG b-wave amplitudes were twofold higher in LE and BN rats compared to those of SD rats (947 ± 129 µV and 892 ± 184 µV, vs 427 ± 138 µV; p = 0.0002 for both). UHR-OCT images showed backward bowing in all groups during IOP elevation, with a return to typical form about 30 min after IOP elevation.
  
  
  
  Differences in the loop-induced responses between the strains are likely due to different inherent retinal morphology and physiology.
authors.affiliation: School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
authors.forename: Akshay
authors.initials: A
authors.lastname: Gurdita
authors.affiliation: Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
authors.forename: Bingyao
authors.initials: B
authors.lastname: Tan
authors.affiliation: Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Joos
authors.affiliation: School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.|Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
authors.forename: Kostadinka
authors.initials: K
authors.lastname: Bizheva
authors.affiliation: School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, N2L 3G1, Canada. vchoh@uwaterloo.ca.
authors.forename: Vivian
authors.identifier: 0000-0001-8197-4082
authors.initials: V
authors.lastname: Choh
mesh_terms: D000208:Acute Disease; D000417:Albinism / Q000503:physiopathology*; D000704:Analysis of Variance; D000818:Animals; D003623:Dark Adaptation / Q000502:physiology; D004596:Electroretinography; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D009798:Ocular Hypertension / Q000503:physiopathology*; D051381:Rats; D011914:Rats, Inbred BN; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000503:physiopathology*; D012165:Retinal Ganglion Cells / Q000502:physiology; D041623:Tomography, Optical Coherence
keywords: Brown Norway; Electroretinography; Intraocular pressure; Long-Evans; Rat; Sprague-Dawley; Ultrahigh-resolution optical coherence tomography