Temporal analysis of electroretinographic responses in fishes with rod-dominated and mixed rod-cone retina

• Published in: General Physiology and Biophysics
• Main Authors: Milošević, Milena, Višnjić Jeftić, Željka, Damjanović, Ilija, Nikčević, Miroslav, Andjus, Pavle R., Gačić, Zoran
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: General Physiol And Biophysics, Bratislava 2009
• Subjects: Prussian carp; Painted comber; Eel; Dogfish shark; Critical flicker frequency; Canicula; Anguilla anguilla
• Online Access: http://rimsi.imsi.bg.ac.rs/handle/123456789/341; https://doi.org/10.4149/gpb_2009_03_276; http://rimsi.imsi.bg.ac.rs/bitstream/id/588/338.pdf

Photoreceptor content of fish retinas could be accessed by comparative electroretinographic (ERG) studies using flickering light stimuli that could separate rod-mediated vision where critical flicker frequency (CFE, frequency when the eye loses its ability to resolve individual light pulses) is usually less than 15 Hz from cone-mediated vision. Four fish species inhabiting different photic environments (small-spotted dogfish shark - Scyliorhinus canicula, eel - Anguilla anguilla, painted comber - Serranus scriba, Prussian carp - Carassius gibelio) were investigated. Dogfish shark b-wave amplitudes significantly decreased at low frequency of stimulation and CFF was reached at 3.2 Hz. A similar effect on the b-wave amplitude was observed in the eel, but CFF occurred at around 20 Hz. Conversely, b-waves of painted comber and Prussian carp remained unaltered under intermittent low-frequency stimulation, and CFFs were around 25 and 30 Hz, respectively. Additional support in accessing the receptor content of fish retinas was given by the characterization of the OFF-response (d-wave) after light adaptation. Monotonous time course of the b-wave dark adaptation indicated a rod dominated retina of the dogfish shark. Observed results indicate that the dogfish shark possesses preponderantly rod retina, that of the eel is rod-dominated, while Prussian carp and painted comber have cone-rich retinae.