(A) CLARITY image of GFAP-labeled astrocytes (red) and GFP-expressing neurons (green) in Thy1-GFP transgenic mice shows close association of astrocytes and CA1 dendrites in the stratum lucidum/radiatum of the hippocampus. High-magnification images (B) and astrocyte-neuron membrane association (yellow; arrow) in stratum lucidum/radiatum (C). Scale bar: 25 μm. (D) SRR expression using Western blot analysis at 24 hpi is not altered in the hippocampus. (E) d-serine levels using chemiluminescence analysis show increased levels at 4 and 24 hpi. (F) Immunohistochemical expression of SRR was reduced in pyramidal cell layer at 3 (G) and 7 (H) dpi, but increased in cells outside that region as compared with sham-treated controls (F). Scale bar: 25 μm. SRR-labeled cells outside the pyramidal cell layer (K) colabel with the astrocytic marker (J) GFAP. No crossreactivity observed in secondary only controls (L and M). Scale bar: 25 μm. (I) SRR levels were reduced at 3 dpi and returned to basal levels by 7 dpi using Western blot analysis. (N) Purification of hippocampal astrocytes from GFAP-GFP mice showed GFP-positive cells were only observed in isolated GLAST⁺ isolated cells. (O) Isolated GLAST⁺ astrocytes express increased levels of SRR at 7 dpi using Western blot analysis. (P) SRR was reduced in the aSRKO hippocampus at 7 dpi using Western blot analysis. (Q) SRR was increased in the nSRKO hippocampus at 7 dpi using Western blot analysis. Data represent mean ± SEM. (D, E, I, O–Q) n = 4–6/group. Student’s t test. *P < 0.05; **P < 0.01; ***P < 0.001, compared with sham-treated controls. ^§§P < 0.01, compared with 3 dpi. For Western blot images, lanes were run on the same gel, but lanes separated by a line were noncontiguous (see Supplemental Figure 2).