Bergmann glia in the cerebellum elaborately ensheathe Purkinje cell dendrites and synapses, and express high levels of Ca2+-permeable glutamate receptors (GluRs). Suppression of the Ca2+ permeability by virus-mediated GluR2 transfer has revealed that GluR-mediated Ca2+ signaling is essential to maintain both structural and functional connections between the glial cell and the glutamatergic synapses.