FIGURE 1.

Wrapping of S100B-containing astrocytic processes around SNc DA neurons is significantly increased only in male mice. (a) A representative confocal mosaic of a mouse midbrain section immunostained for S100B (green) and TH (red), scale bar = 300 μm. Subregions of the midbrain are indicated with dotted lines (SNc, substantia nigra pars compacta; SNr, substantia nigra pars reticulata; VTA, ventral tegmental area). (b) Representative high magnification confocal images of S100B and TH expression in the SNc (top left) and VTA (top right), NeuN expression in the SNc is shown in the lower panel with white arrows denoting TH− neurons, scale bar = 10 μm. (c) Schematic of astrocyte wrapping analysis, described in detail in the methods section. (d) Graphs showing astrocyte wrapping of neuronal somata (left panel) and S100B expression intensity (right panel) across specific midbrain subregions in male and female mice. n = 8 midbrain sections from three male and three female mice. All errors are SEM; p-values are based on two sample t tests except for SNc TH⁺, VTA TH⁺, and SNc TH⁺, SNr TH⁻ comparisons which are Mann–Whitney tests. (e) Schematic for genetically expressing membrane bound GCaMP6f in astrocytes using AAV 2/5 GfaABC₁D-Lck-GCaMP6f, including representative confocal images of astrocyte processes enveloping TH⁺ neurons in the SNc