Ventral midbrain astrocytes display unique physiological features and sensitivity to dopamine D2 receptor signaling

Morphology of ventral midbrain and telencephalic astrocytes. a Coronal brain section from a P60 Aldh1L1-eGFP mouse immunostained for Aldh1L1 (red). b Images taken from P60 Aldh1L1-eGFP mouse section showing density and tissue coverage by eGFP+ astrocyte processes in the ventral tegmental area (VTA), cortex (CTX), and hippocampus (HPC). c Closeup of individual eGFP+ astrocytes. d Quantification of eGFP+ astrocyte density in P60 animals. One-way ANOVA, F？=？0.6611, p？=？0.5441, N？=？5 animals, 1 section per animal, per region. e Quantification of percent tissue coverage by eGFP+ astrocyte processes in P60 animals (see Methods for details). One-way ANOVA, F？=？7.866, p？=？0.0025; Bonferroni post hoc tests for CTX vs HPC t？=？0.1441, CTX vs VTA t？=？3.536, HPC vs VTA t？=？3.396 (**p？<？0.01). N？=？8–9 sections, 4–5 animals per region. f Quantification of eGFP+ astrocyte soma size in P60 animals. One-way ANOVA, F？=？19.52, p？<？0.0001; Bonferroni post hoc tests for CTX vs HPC t？=？1.899, CTX vs VTA t？=？4.179, HPC vs VTA t？=？6.078 (***p？<？0.0001). N？=？6–8 sections, 4–6 animals per region. g Example scatter plot of one FACS experiment, with forward scatter values on the x-axis and FITC channel intensity on the y-axis. Circle indicates eGFP+ astrocyte considered in analysis. h Forward scatter values from one FACS experiment in which Aldh1L1-eGFP tissue microdissected from ventral midbrain, CTX, and HPC were dissociated into single-cell suspensions and analyzed by flow cytometry. Graph shows aggregate forward scatter values of eGFP+ astrocytes from the three regions. i Quantification of average forward scatter values (per animal/experiment) of eGFP+ astrocyte from ventral midbrain, CTX, and HPC. One-way ANOVA, F？=？31.06, p？<？0.0001; Bonferroni post hoc tests for CTX vs HPC t？=？0.5599, CTX vs ventral midbrain t？=？0.7089, HPC vs ventral midbrain t？=？6.529 (***p？<？0.001). N？=？6 animals/experiment