GABA receptor binding site “induction” in rabbit retina after nipecotic acid treatment: Changes during postnatal development

摘要

The development of the GABA system in the rabbit retina was studied. The number of high- and low-affinity GABA receptor binding sites increased in a sigmoidal manner, with the curve for the low-affinity sites lagging 2–3 days behind that for the high-affinity sites. TheKDfor both high-(17.5 nM) and low-affinity (138.0 nM) sites remained constant during development. Treatment of isolated eyecups with the uptake blocker nipecotic acid resulted in an increase in theBmaxfor high-affinity sites in developing tissue with the maximum sensitivity around eye opening; mature tissue exhibited a decrease inBmax. In contrast, a gradual decrease in sensitivity to stimulation of the low-affinity sites occurred. These data indicate that the “trophic” action of GABA is limited to the time when the tissue is devel