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PHOTIC RELEASE OF RADIOACTIVITY FROM RABBIT RETINA PRELOADED WITH [ 3 H]GABA
Author(s) -
BAUER BIRGITTA
Publication year - 1978
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.1978.tb01353.x
Subject(s) - retina , efflux , retinal , stimulation , neurotransmitter , rabbit (cipher) , chemistry , gamma aminobutyric acid , glutamate receptor , biophysics , biology , biochemistry , endocrinology , neuroscience , receptor , statistics , mathematics
The in vitro release of radioactivity by light from rabbit retina was studied after intravitreal injection of [ 3 H]GABA (γ‐aminobutyric acid). The site of uptake of [ 3 H]GABA into the retina after intravitreal injection was checked by autoradiography and was localized at 2 h after the injection mainly in glia but at 4 h in amacrine cells and some ganglion cells. If the retina loaded with [ 3 H]GABA was stimulated by light flashes the efflux of radioactivity increased significantly. Chromatographic analysis of the superfusate demonstrated that [ 3 H]GABA was released by light stimulation. However, the efflux was not elicited by constant light, and was abolished in a medium containing 20 mM Mg++ and 0.2 mM++. When the metabolism of GABA was inhibited by amino‐oxyacetic acid, light flashes no longer increased the efflux of radioactivity significantly. No light‐evoked release of radioactivity could be demonstrated from glia. Pentobarbitone inhibited the spontaneous efflux and prior anaesthetization with pentobarbitone abolished the light‐evoked release. These results support the view that GABA is a retinal neurotransmitter in the rabbit.