Prominent Expression of Two Forms of Glutamate Decarboxylase in the Embryonic and Early Postnatal Rat Hippocampal Formation

摘要: Immunohistochemical methods were used to determine the earliest times of detection for two forms glutamate decarboxylase (GAD67 and GAD65) in embryonic early postnatal rat hippocampal formation whether their distribution patterns differed from each other those adult. Both GAD67- GAD65-containing neurons observed as day 17 (E17)-E18 hippocampus E19 dentate gyrus, this was substantially earlier than GAD had been detected previously formation. The isoforms displayed very similar patterns, but these distinctly different From E17 E20, GAD67 GAD65 expressed neuronal cell bodies throughout marginal zones (future dendritic layers), relatively few existed within principal body layers, where GAD-positive are frequently concentrated At E21 1 (P1), there a sudden shift predominance GAD-containing developing regions meshwork processes with terminal-like varicosities same regions. This pattern also contrasted that adult, which GAD-labeled terminals highly layers. Electron microscopic observations at P1 confirmed axon-like appearance demonstrated immunoreactivity consistently localized vesicle-filled often closely apposed and, some instances, established synaptic contacts profiles. present identification an abundance structures marked change during development complement recent developmental changes functioning GABA system provide additional support involvement neurotransmitter development.