Figure 4. SAVA immunolesions compromise GABAergic but not glutamatergic neuronal identity markers in the rodent hippocampus. A–A2, Comparison of parvalbumin+ local-circuit interneurons in control (A), unc-Ab-treated (A1), or SAVA-lesioned (A2) hippocampi of mice 12 d postlesion. A3, Distribution of parvalbumin immunofluorescence along the pyramidal layer in the CA1-CA3 subfields of the treatment groups. Arrowheads denote the lateral extremities, while dashed line identifies the extent of the surface area showing reduced parvalbumin immunoreactivity in the CA1–3 subfields. Note the sharp SAVA lesion border (arrowheads), as revealed by the lack of parvalbumin+ terminals, in A3, B, B1, The loss of parvalbumin+ interneurons and their terminals was found associated with reduced density of NeuN+ CA1 pyramidal cells. C–C3, Quantitative analysis of lesion extent along the anterior–posterior axis of the hippocampus (C, C1; “spared surface area” refers to the percentage of CA1 region harboring parvalbumin immunoreactivity), the density of parvalbumin+ boutons (C2) and somata (C3). **p < 0.01 vs contralateral/unc-Ab groups. D–F2, We confirmed the SAVA-induced loss of GABAergic interneurons by using GAD67 (D, D1), SAT1 (E–E2) and CB1Rs (E–F2) as alternative markers of perisomatic basket cells. Arrowheads in D and E2 point to perisomatic profiles, asterisks denote the location of pyramidal cells. The finding that SAVA selectively eliminates CB1R immunoreactivity in the CA1 subfield (open arrowheads) but not dentate gyrus (solid arrowheads), and leaves VGLUT1 distribution unchanged reinforces SAVA's specificity toward inhibitory targets. G, Lateral extent of SAVA neurotoxicity in the rat hippocampus. H–I1, SAVA infusion in the rat hippocampus replicated prior findings from mouse, i.e., reduced parvalbumin (H1) and GAD67 immunoreactivities (I1) relative to controls (H, I). CA1–CA3, Cornu ammonis subfields; DG, dentate gyrus; Th, thalamus; or, stratum oriens; pyr, stratum pyramidale; rad, stratum radiatum. Scale bars: A–A2, F–F2, 500 μm; B1, D1, H–I1, 25 μm; E–E2, 15 μm.