Distribution and functional significance of rodent cerebellar glycogen.

The mammalian brain stores glucose, the main circulating energy substrate, as glycogen. In rodents, the cerebellum contains relatively high glycogen levels, yet its cellular and subcellular distribution remains poorly defined. Using monoclonal antibodies against glycogen, we examined its distribution in the mouse cerebellar cortex. Glycogen was predominantly localized to Bergmann glia (BG) processes in the molecular layer and was also detected in Purkinje cells (PCs), the principal cerebellar neurons. To assess the functional significance of cerebellar glycogen, we analyzed behavior in mice lacking glycogen synthase 1 (Gys1) in BG or PCs using a floxed Gys1 line. Gys1 deficiency in either PCs or GFAP-positive cells reduced anxiety-like behavior, whereas combined deletion caused PC degeneration and ataxia. These findings reveal a critical role for glycogen metabolism in both astrocytes and neurons in cerebellar function.