Fig 2: Baclofen increases myelin-related protein synthesis in organotypic cultures without altering the proliferation ratio of oligodendroglial lineage. (a) Oligodendroglial cells, distinguished as Olig2+ cells (red), are positive for GABAB1 and GABAB2 subunits (green) of GABABRs in cerebellar slices of P5-P7 rats. (b) Mature oligodendrocytes (OLs), identified as APC+ cells (red), express GABAB1, and GABAB2 subunits (green) of GABABRs in the same preparations. Arrows indicate double-stained cells and arrowheads show the cell magnified in the corresponding inset. Scale bars = 20 µm. (c) Representative western blot image-showing expression of myelin-associated glycoprotein (MAG), CNPase, and MBP proteins in control and baclofen-treated cerebellar slices. Quantification of MAG (d), CNPase (e), and myelin basic protein (MBP) (f) expression normalized to GAPDH values. *p < .05 and ** p < .01 versus control; paired Student's t-test. (g) Representative images showing immunofluorescence of mature OLs (APC+, red) and total oligodendroglial cells (Olig2+, green) co-labeled with EdU (cyan) to identify mature OLs (APC+) and Olig2+ cells in cerebellar slices in the indicated condition. Arrows indicate mature OLs (APC+Olig2+) or newly generated oligodendroglial cells (Olig2+EdU+). Scale bar = 50 µm. Quantification of (h) percentage of mature OL from total oligodendroglial cell pool (APC+Olig2+/Olig2+) and (i) density of newly formed oligodendroglial cells (Olig2+EdU+), in the indicated conditions. One-way ANOVA followed by Tukey's post-test. (j) Optic nerve-retina unit from P11 PLP-DsRed transgenic mice. Scale bar = 500 µm. (k) Optic nerves explants cultured in control conditions (left) or in presence of baclofen (right) showing DsRed fluorescent signal. Scale bars = 100 µm; higher magnification scale bar = 315 µm. (l) Quantification of DsRed fluorescent signal in control and treated optic nerve explants. *p < .05 versus control; unpaired Student's t-test. (a–f): Control and bac 6 slices from different animals. (g–i): Control 15, GABA 18, and bac 18 images from cerebellar slices. (j–l): Control 27, bac 24 images from optic nerve explants

Fig 3: GABAB receptors are expressed by oligodendrocyte progenitor cell (OPCs) and mature oligodendrocytes from the mouse spinal cord. (a) Confocal images showing OPCs (Nkx2.2+, gray) expressing GABAB1 (red) and GABAB2 (green) subunits of GABABRs in the dorsal funiculus of the spinal cord of unlesioned mice. (B, C) Confocal images showing OPCs (Nkx2.2+, red) (b) and mature OLs (APC+, red) (c) expressing GABAB1 (green, top) and GABAB2 (green, bottom) subunits of GABABRs in the dorsal funiculus of the spinal cord of control lysolecithin (LPC)-injected mice. White dash line indicates lesion border. Arrowheads point at cells shown at higher magnification in each photograph. Scale bars = 50 µm. Higher magnification = 10 µm