Impairment of motor coordination, Purkinje cell synapse formation, and cerebellar long-term depression in GluR delta 2 mutant mice.

Of the six glutamate receptor (GluR) channel subunit families identified by molecular cloning, five have been shown to constitute either the AMPA, kainate, or NMDA receptor channel, whereas the function of the delta subunit family remains unknown. The selective localization of the delta 2 subunit of the GluR delta subfamily in cerebellar Purkinje cells prompted us to examine its possible physiological roles by the gene targeting technique. Analyses of the GluR delta 2 mutant mice reveal that the delta 2 subunit plays important roles in motor coordination, formation of parallel fiber-Purkinje cell synapses and climbing fiber-Purkinje cell synapses, and long-term depression of parallel fiber-Purkinje cell synaptic transmission. These results suggest a close relationship between synaptic plasticity and synapse formation in the cerebellum.