Glia-synapse interaction through Ca2+-permeable AMPA receptors in Bergmannglia

Glial cells express a variety of neurotransmitter receptors, Notably, Bergm ann glial cells in the cerebellum have Ca2+-permeable alpha -amino-3-hydrox y-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors (AMPAR s) assembled without the GluR2 subunit, To elucidate the role of these Ca2-permeable AMPARs, we converted them into Ca2+-impermeable receptors by ade noviral-mediated delivery of the GluR2 gene. This conversion retracted the glial processes ensheathing synapses on Purkinje cell dendritic spines and retarded the removal of synaptically released glutamate, Furthermore, it ca used multiple innervation of Purkinje cells by the climbing fibers. Thus, t he glial Ca2+-permeable AMPARs are indispensable for proper structural and functional relations between Bergmann glia and glutamatergic synapses.