April 2010
Volume 51, Issue 13
Free
ARVO Annual Meeting Abstract  |   April 2010
Interphotoreceptor Retinoid-Binding Protein and Its Role in the Mouse Cone Visual Cycle
Author Affiliations & Notes
  • A. V. Kolesnikov
    Ophthalmology and Visual Sciences, Washington University in St Louis, St Louis, Missouri
  • R. O. Parker
    Ophthalmology, Medical University of South Carolina, Charleston, South Carolina
  • R. K. Crouch
    Ophthalmology, Medical University of South Carolina, Charleston, South Carolina
  • V. J. Kefalov
    Ophthalmology and Visual Sciences, Washington University in St Louis, St Louis, Missouri
  • Footnotes
    Commercial Relationships  A.V. Kolesnikov, None; R.O. Parker, None; R.K. Crouch, None; V.J. Kefalov, None.
  • Footnotes
    Support  NIH Grant EY019312 and RPB Career Development Award (VJK), NIH EY004939 and RPB Senior Scholars Award (RKC), and RPB Medical Student Award (ROP).
Investigative Ophthalmology & Visual Science April 2010, Vol.51, 1115. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      A. V. Kolesnikov, R. O. Parker, R. K. Crouch, V. J. Kefalov; Interphotoreceptor Retinoid-Binding Protein and Its Role in the Mouse Cone Visual Cycle. Invest. Ophthalmol. Vis. Sci. 2010;51(13):1115.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose: : Interphotoreceptor retinoid-binding protein (IRBP) has been suggested to play an important role in maintaining cone structure and function by facilitating retinoid transport between cones and the RPE. However, its role in the cone-specific retina visual cycle is unknown. To address this issue we generated a double knockout Irbp-/-/Tα-/- (rod transducin alpha) mouse lacking rod signaling and developed a method of transretinal ERG recordings from mouse eyecups.

Methods: : We recorded cone ERG responses (a-wave) from isolated mouse retinas or intact eyecups where the retina was attached to the RPE (1-2 m.o. animals). Contributions of the b-wave and slow glial component were blocked pharmacologically. We compared the kinetics of cone photoresponses and photosensitivity recovery following full M-cone pigment bleach in Irbp-/-/Tα-/- vs. Tα-/- control animals.

Results: : We found that Irbp-/-/Tα-/- cones were two times less sensitive and their responses had significantly slower shutoff (300 ms vs. 180 ms) compared to Tα-/- cones; both possibly due to mild degeneration. Surprisingly, the kinetics of cone photosensitivity recovery was not substantially different between Irbp-/-/Tα-/- and Tα-/- mice (time constants 240 s vs. 210 s for eyecups; and 100 s vs. 70 s for isolated retinas, respectively). Notably, in both mouse genotypes sensitivity recovery in eyecup was biphasic, with a rapid phase similar to that in isolated retina, followed by a slower phase that produced 2-fold higher final recovery of sensitivity in eyecup compared to the retina (60% vs. 34% by 30 min postbleach, on average). Background light adaptation function of Irbp-/-/Tα-/- cones was shifted ca. 2-fold to dimmer light intensities both in retina and eyecup, most likely due to their longer integration time.

Conclusions: : Our results indicate that IRBP is apparently not critical for the timely recovery of mouse cone photosensitivity after bright illumination, that is for the operation of the cone-specific retina visual pathway. Cone dark adaptation in eyecup was biphasic, with a rapid phase presumably due to the retina visual cycle and a slow phase due to the RPE.

Keywords: electrophysiology: non-clinical • photoreceptors • retinoids/retinoid binding proteins 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×