Figure 3.

Na⁺ and K⁺ mapping of the ischemic brain (rat #5). (a,b) Pseudocolor images of the ²³Na slope superimposed over the grayscale 3D reconstruction of the brain from histological 35-µm-thick sections. (c,d) K⁺-stained slices cut at 4.4 h post MCAO. (e,f) ²³Na slope (black) and [K⁺]_br (red) profiles along the ribbons in the ischemic hemisphere (white or color arcs in (a)–(d)) in the dorsal-to-ventral direction. The coronal sections were taken at the rostral (bregma −0.4 mm, a,c,e) and caudal (bregma −3 mm, b,d,f) levels. (1) Dorsal ischemic edge; (2) central ischemic core; (3) ventral ischemic edge. Estimated [Na⁺] and [K⁺] in ipsilateral and homotopic contralateral ROIs (white or color squares in (a)–(d)) in regions 1–3 are given in Table 3. (g) 3D reconstruction of the brain from 21 co-registered K⁺-stained coronal slices (0.7-mm separation) as viewed from the front-right perspective. Regions with [K⁺]_br below 48 ± 4 mEq/kg (based on Gaussian-filtered images, to improve low-K⁺ ROI contiguity) are shown in yellow to highlight the peripheral ischemic core surrounding the central ischemic core. ROI of maximum ²³Na slope corresponding to the slope range of 11.4 to 15.6%/h and overlapping the low-K⁺ ROI is shown in red.