QUANTITATIVE HISTOCHEMISTRY OF GLUTAMATE DECARBOXYLASE IN THE RAT HIPPOCAMPAL REGION

Abstract

Abstract— The distribution of glutamate decarboxylase (GAD) was studied in hippocampus regio superior and in area dentata. In both regions the enzyme showed a bimodal distribution profile with peak activities in the molecular and pyramidal layers of hippocampus, and in the molecular and granular layers of area dentata. The pyramidal and granular layers contain the terminals and perikarya of inhibitory intrinsic neurones, the basket cells. The molecular layers contain neurones of similar morphology but with unknown function. GAD showed a very low activity in fimbria, a major pathway of fibres efferent and afferent to the hippocampal region.The data are consistent with GAD being concentrated within the inhibitory local neurones of the hippocampal region.