• KSBNS 2024


Short Communication

Exp Neurobiol 2018; 27(3): 210-216

Published online June 30, 2018

© The Korean Society for Brain and Neural Sciences

Blue-on-Green Flash Induces Maximal Photopic Negative Response and Oscillatory Potential and Serves as a Diagnostic Marker for Glaucoma in Rat Retina

Su Jin Park1,2, Sun Sook Paik1,2*, Ji-Yeon Lee1, Su-Ja Oh1 and In-Beom Kim1,2,3*

1Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul 06591, 2Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, 3Catholic Institute for Applied Anatomy, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea

Correspondence to: *To whom correspondence should be addressed.
Sun Sook Paik
TEL: 82-2-2258-7268, FAX: 82-2-536-3110
In-Beom Kim
TEL: 82-2-2258-7263, FAX: 82-2-536-3110

Received: April 26, 2018; Revised: May 23, 2018; Accepted: May 28, 2018

The purpose of this study was to investigate the application of various electroretinography (ERG) to the diagnosis of inner retinal dysfunction induced by mild intraocular pressure (IOP) elevation in a rat glaucoma model. For inner retinal function measurements, available photopic ERG protocols were applied under various light conditions including monochromatic combinations, which complement conventional scotopic ERG. Three episcleral veins in the right eyes of Sprague-Dawley rats were cauterized to induce an experimental model of glaucoma, leading to mild IOP elevation. ERG responses were measured before surgery and at 1, 2, 4, and 8 weeks after cauterization. We first confirmed that the amplitude reduction in the standard photopic b-wave was almost comparable to the amplitudes of scotopic a- and b-waves in glaucomatous eyes over time. We have implemented additional photopic ERG protocols under different stimulus conditions, which consisted of a longer duration and different monochromatic combinations. Such a change in the stimulations resulted in more pronounced differences in response between the two groups. Especially in normal animals, blue stimulation on a green background produced the largest b-wave and photopic negative response (PhNR) amplitudes and caused more pronounced oscillatory potential (OP) wavelets (individual components). In glaucomatous eyes, blue stimulation on a green background significantly reduced PhNR amplitudes and abolished the robust OP components. These results, by providing the usefulness of blue on green combination, suggest the applicable photopic ERG protocol that complements the conventional ERG methods of accessing the progression of glaucomatous damage in the rat retina.

Graphical Abstract

Keywords: Electroretinography, Photopic negative response, Oscillatory potential, Glaucoma, Rat retina