July 2018
Volume 59, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2018
A computational method for determining opsin peak absorbance wavelengths from zebrafish PIII ERG responses
Author Affiliations & Notes
  • Ralph F Nelson
    Basic Neurosciences Program, NINDS NIH, Bethesda, Maryland, United States
    Anatomy and Regenerative Biology, George Washington University, Washington DC, District of Columbia, United States
  • Annika Balraj
    Basic Neurosciences Program, NINDS NIH, Bethesda, Maryland, United States
    Anatomy and Regenerative Biology, George Washington University, Washington DC, District of Columbia, United States
  • Tara Suresh
    Basic Neurosciences Program, NINDS NIH, Bethesda, Maryland, United States
  • Meaghan Torvund
    Basic Neurosciences Program, NINDS NIH, Bethesda, Maryland, United States
    Neuroscience, University of Arizona, Tuscon, Arizona, United States
  • Sara Stokes Patterson
    Basic Neurosciences Program, NINDS NIH, Bethesda, Maryland, United States
    Ophthalmology, University of Washington, Seattle, Washington, United States
  • Footnotes
    Commercial Relationships   Ralph Nelson, None; Annika Balraj, None; Tara Suresh, None; Meaghan Torvund, None; Sara Patterson, None
  • Footnotes
    Support  Intramural Research Program, National Institute of Neurological Disorders and Stroke
Investigative Ophthalmology & Visual Science July 2018, Vol.59, 600. doi:
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      Ralph F Nelson, Annika Balraj, Tara Suresh, Meaghan Torvund, Sara Stokes Patterson; A computational method for determining opsin peak absorbance wavelengths from zebrafish PIII ERG responses. Invest. Ophthalmol. Vis. Sci. 2018;59(9):600.

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

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Abstract

Purpose : To determine, using electroretinography, which of 8 cone opsin types (Chinen et al, 2003) are expressed in the red, green, blue and UV cone types of zebrafish over the course of eye development.

Methods : Microelectrodes are inserted into perfused, in vitro, roy/roy zebrafish eyes. Eyes are perfused with oxygenated MEM containing Na Aspartate to saturate post-synaptic glutamatergic receptors and to isolate cone PIII responses, evoked at 9 wavelengths (330-650nm) with either infrared (IR), red (627nm) or blue (418nm) backgrounds. Spectra were fit by a ‘sum of Hill functions’ model (Nelson & Singla, 2009), where each cone is represented by a Hill function whose semi-saturation parameter is adjusted with wavelength according to a spectral nomogram function for zebrafish cone opsins (Hughes et al, 1998; Palacios et al, 1996). Peak opsin absorbance of individual cone signals is a calculated fit parameter. For each age and background treatment, large datasets of over 1000 PIII spectral signals were compiled from 6-13 eyes, and fit as a group to the spectral function.

Results : The mean larval (5, 6, 7, and 12 dpf) LWS opsin peak was 555.9±1.5 nm. The peak was little affected by chromatic backgrounds. The mean adult LWS opsin peak was 573.5±2.1 nm for IR, 418nm and white backgrounds. For red backgrounds, the adult LWS peak was 564.7±0.1 nm. The mean larval RH2 (green cone) opsin peak was 465.6 ±3.0 nm, tending towards shorter wavelengths with 418nm backgrounds, and longer wavelengths with 627nm backgrounds. The mean adult RH2 peak (all backgrounds) was 475.1±3.7 nm.

Conclusions : Adult LWS and RH2 opsin peaks are like published measurements with microspectrophotometric or microelectrode recording of single cones. The larval RH2 peak (465.6nm) is like the 467nm value for RH2-1 of Chinen et al. RH2-1 is expressed in larvae, but adults express additional longer wavelength RH2’s (Takechi and Kawamura, 2005), consistent with a slightly longer wavelength RH2 peak (475.1nm) found in adults. Both the larval (555.9nm) and adult (573.5nm) peaks are longer than those of Chinen (LWS-2, 548nm; LWS-1, 558nm). Invariance of the larval LWS peak with selective chromatic adaptation suggests a single LWS opsin. The shortening of the adult LWS peak by red backgrounds suggests mixed LWS-1, LWS-2 expression in adults (Takechi and Kawamura, 2005).

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

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