Fig. 2. Immunohistochemical analysis of pRyR1Ser²⁸⁴⁰ in rat LAT and GAS muscles. (A and D) Double staining against (a) α-actinin and (b) pRyR1Ser²⁸⁴⁰ shows localizations of Z-disks (α-actinin) in close vicinity of junctional sarcoplasmic reticuli (pRyR1Ser²⁸⁴⁰) that surround t-tubuli, which are located in the transitional zone of A- and I-bands in skeletal muscles. The merged picture is demonstrated in (c). Fold changes of pRyR1Ser²⁸⁴⁰ in LAT (B) and GAS (E) muscle under 1xLevel and 1xDownhill conditions compared to CON conditions. pRyR1Ser²⁸⁴⁰ shows significantly elevated levels in both muscles after acute exercise stimulations. Representative pRyR1Ser²⁸⁴⁰ staining in LAT (C) and GAS (F) muscle under CON, 1xConc, and 1xEcc conditions. The upper panels depict the pRyR1Ser²⁸⁴⁰ pattern; the lower panel shows control slides that were incubated with 0.8% BSA instead of primary antibody. ** p<0.01, *** p<0.001. Bar in (A and D) is 5 µm, bar in (C and F) is 50 µm. In total, n=2000 muscle fibers were measured per intervention group.