GLUL and multiple sclerosis: Regarding GS being highly expressed in astrocytes, it can also be expressed in myelinating oligodendrocytes in the granular layer of the cerebellum [58] and in the spinal cord of mice and humans [59], particularly in chronic pathological conditions, such as amyotrophic lateral sclerosis and multiple sclerosis, suggesting that the reduction in GS expression observed in this study may not be solely from an astrocytic source.