Fig. 5.
Skeletal muscle RyR1 isolated from aged MCat mice is remodeled and exhibits reduced single-channel open probability (Po). (A) Representative immunoblots from triplicate experiments of immunoprecipitated RyR1 from aged murine EDL. (B) Bar graphs showing quantification of the immunoblots in A; DNP: 2,4-dinitrophenylhydrazone. (C) Representative RyR1 single-channel current traces. Channel openings are shown as upward deflections and the closed (c-) state of the channel is indicated by horizontal bars in the beginning of each trace. Tracings from over 2 min of recording for each condition showing channel activity at two time scales (5 s in upper trace and 500 ms in lower trace) as indicated by dimension bars, and the respective Po (open probability), To (average open time), and Tc (average closed time) are shown above each trace. The activity of the channel indicated by the thick black bar is shown on the expanded time scale (the 500 ms trace below). (D) Bar graph summarizing Po at 150 nM cytosolic [Ca2+] in young WT (n = 6), aged WT (n = 5), young MCat (n = 7), and aged MCat (n = 5) channels. Data are mean ± SEM (*P < 0.05, **P < 0.01 vs. young WT, #P < 0.05, #P < 0.01 vs. aged WT, ANOVA).