Benzodiazepine receptors in the visual structures of monocularly deprived rats. Effect of light and dark adaptation.
In 25-day-old rats with one eyelid sutured at the age of 10 days, the binding of [3H]flunitrazepam in the visual structures (retina, lateral geniculate nucleus, superior colliculus, visual cortex) and frontal cortex was determined. Monocular visual deprivation (MD) resulted in a significant decrease of the [3H]flunitrazepam binding in the retina of the open eye to about 76% of the control value. No changes in [3H]flunitrazepam binding were detectable under these conditions in the central visual structures examined and the non-visual cortical region. Scatchard analysis indicated that the changes found in the retina of the open eye of MD rats are due to a decreased binding affinity only, the maximum receptor number being unaffected. Eight hours after re-opening the sutured eyelid of 25-day-old MD rats, benzodiazepine binding in the open eye was increased to the control level, whereas the binding in the retina of the re-opened eye remained unchanged in comparison to control animals. Dark adaptation of 25-day-old control rats resulted in an increased [3H]flunitrazepam binding in the retina by 28% compared to that detectable in the retina of light-adapted animals. In contrast, dark-adaptation of MD rats did not affect [3H]flunitrazepam binding in the retina of both eyes in comparison to that found in the corresponding retina of light-adapted MD animals. The data obtained suggest a physiological coupling between both retinas, possibly mediated through centres inside of the central nervous system.
Rothe
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Schliebs
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Bigl
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D000818:Animals; D003623:Dark Adaptation; D005260:Female; D005829:Geniculate Bodies / Q000032:analysis; D008297:Male; D051381:Rats; D011963:Receptors, GABA-A / Q000032:analysis*; D012160:Retina / Q000032:analysis*; D012683:Sensory Deprivation / Q000502:physiology*; D013477:Superior Colliculi / Q000032:analysis; D009435:Synaptic Transmission; D014785:Vision, Ocular / Q000502:physiology*; D014793:Visual Cortex / Q000032:analysis; D014795:Visual Pathways / Q000032:analysis*; D005680:gamma-Aminobutyric Acid / Q000502:physiology
D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid