Photopic Electroretinograms of mGluR6-Deficient Mice

Abstract

Purpose: To study the properties of the photopic electroretinograms (ERGs) of the metabotropic glutamate receptor subtype 6 (mGluR6)-deficient mice and to investigate the contribution of cone ON-and OFF-pathways to the mouse photopic ERGs. Methods: Photopic ERGs were recorded from mGluR6-deficient and wild-type mice. Photopic ERGs were also recorded after an intravitreous injection ofcis-2,3 piperidine dicarboxylic acid (PDA) to block the transmission of signals from the photoreceptors to the OFF-bipolar cells, horizontal cells, and other inner retinal neurons. Results:The amplitude of the b-wave of the photopic ERG was severely reduced in mGluR6-deficient mice, but a small, slow, positive component was seen after the a-wave. Intravitreous injection of PDA eliminated this positive component. Conclusions: The mGluR6-deficient mouse is a useful animal model to study the contribution of the ON-and OFF-pathways to the mouse ERG.

KEYWORDS:

• cones, electroretinogram
• knockout
• metabotropic glutamate receptor subtype 6 (mGluR6)
• photopic