The antibiotic neomycin abolishes directional selectivity in rabbit retinal ganglion cells

Abstract

1. 1. Extracellular recordings from ON/OFF directionally selective ganglion cells in superfused rabbit retinas were made to study the effect of the aminoglycoside antibiotic, neomycin, on the responses of these cells to a moving light stimulus. 2. 2. Neomycin, at 480–800 μM, reversibly abolished the directional selectivity in these ganglion cells by bringing out a response to movement in one (“null”) direction that was similar in magnitude to the response to movement in the reverse (“preferred”) direction. 3. 3. Gentamicin, streptomycin, and tobramycin were also able to abolish directional selectivity in these ganglion cells but only at concentrations greater than 1000 μM. 4. 4. It is proposed that neomycin abolishes directional selectivity in rabbit retinal ganglion cells by blocking ω-conotoxin MVIIC-sensitive Ca 2+ channels in the retina.