December 2002
Volume 43, Issue 13
Free
ARVO Annual Meeting Abstract  |   December 2002
Light-adaptation In Rat Rods At Different Temperatures
Author Affiliations & Notes
  • S Nymark
    Lab of Biomedical Engineering Helsinki University of Technology Espoo Finland
  • C Haldin
    Dept of Biosciences University of Helsinki Helsinki Finland
  • H Suominen
    Lab of Biomedical Engineering Helsinki University of Technology Espoo Finland
  • K Donner
    Dept of Biosciences University of Helsinki Helsinki Finland
  • A Koskelainen
    Lab of Biomedical Engineering Helsinki University of Technology Espoo Finland
  • Footnotes
    Commercial Relationships   S. Nymark, None; C. Haldin, None; H. Suominen, None; K. Donner, None; A. Koskelainen, None. Grant Identification: Support: Academy of Finland 49947
Investigative Ophthalmology & Visual Science December 2002, Vol.43, 1419. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      S Nymark, C Haldin, H Suominen, K Donner, A Koskelainen; Light-adaptation In Rat Rods At Different Temperatures . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1419.

      Download citation file:


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

      ×
  • Supplements
Abstract

Abstract: : Purpose: Mammalian rods have been reported to light-adapt much less efficiently than rods of lower vertebrates. Our hypothesis is that this difference may be largely due to the different temperatures at which the experiments have been done. We therefore wanted to study how light-adaptation in rat rods changes with temperature. Methods: Aspartate-isolated rod photoresponses to 519 nm flashes were recorded by electroretinogram (ERG) technique across isolated rat (Rattus norvegicus) retinas. Fractional sensitivities (defined by the half-saturating flash intensity) were determined from five-point intensity-response data in darkness and under steady background illuminations (up to 103 Rh*/s, 503 nm) in the temperature range 12-36 °C. Results: At 36 °C the background intensity producing 10-fold sensitivity reduction (I10) was 500-800 Rh*/s, in agreement with the value 500-1000 Rh*/s obtained from the intact human eye (Friedburg et al. 2001, J. Physiol. 534.1, 217-242). As temperature was lowered, I10 decreased as follows: ca. 200 Rh*/s at 28 °C, 40 Rh*/s at 20 °C and 7 Rh*/s at 12 °C. In frog (Rana temporaria) at 16.5 °C, I10 is about 20 Rh*/s (Donner et al. 1995, Vision Res. 35, 2255-2266). Conclusion: At body temperature, I10 was similar to that in human rods. At similar (lower) temperatures, I10 of rat rods was comparable to that of frog rods. The results contradict the idea that there are basic differences in rod light-adaptation between mammals and amphibians.

Keywords: 517 photoreceptors • 384 dark/light adaptation 
×
×

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.

×