LIGHT-MICROSCOPIC AND ELECTRON-MICROSCOPIC LOCALIZATION OF THE GLUTAMATE-RECEPTOR CHANNEL DELTA-2 SUBUNIT IN THE MOUSE PURKINJE-CELL

The localization of the glutamate receptor channel delta 2 subunit was investigated by immunohistochemistry. The delta 2-immunoreactivity wa s observed exclusively in the molecular layer of the cerebellar cortex . The electron microscopic analysis showed that the delta 2 subunit wa s localized in the dendritic spines of the Purkinje cells. The immunop ositive spines often formed synaptic contacts with parallel fiber vari cosities. As for the Purkinje cells ectopically localized in the cereb ellar nuclei and brain stem, the dendritic shafts and cell bodies were strongly labeled. These ectopic Purkinje cells also formed asymmetric al synapses at the delta 2-immunopositive dendritic spines. Considerin g the specific localization of the delta 2 subunit in the postsynaptic site of the Purkinje cells, the subunit is suggested to be involved i n the excitatory synaptic transmission in the cells, as a component of the glutamate receptor channel.