Autoradiographic localization of strychnine-sensitive glycine receptor in bovine adrenal medulla

The presence of an uptake system and a functional glycine receptor in adrenal medulla chromaffin cells was investigated using an autoradiographic technique in adrenal gland slices. Specific 3[H]glycine binding was observed in both adrenal cortex and medulla slices, while only specific binding of [3H]strychnine was seen only in chromaffin cells and was not associated with cortical cells. [3H]Glycine binding sites in the cortex are apparently different from those of [3H]strychnine binding sites in the medulla since excess strychnine does not displace [3H]glycine from adrenal cortex but does so from medulla. This difference supports biochemical evidence for glycine transport into medulla cells and glycine receptor sites on the chromaffin cell membrane.