Figure 5.

Effect of oxygen tension and GSH/GSSG on wt-RyR1 and C3635A RyR1 activities. Specific [³H]ryanodine binding to membrane fractions prepared from HEK293 cells expressing wt-RyR1 (A) or C3635A RyR1 (B) was determined in 10 μM free Ca²⁺ medium in the absence or presence of 5 mM GSH or 5 mM GSSG and either in pO₂ ≈ 10 mmHg (white bars) or pO₂ ≈ 150 mmHg (black bars). [³H]Ryanodine-binding data are the means ± SD of three to six experiments. *, P < 0.05 compared with the controls in pO₂ ≈ 10 mmHg and ≈ 150 mmHg, respectively. #, P < 0.05 compared with controls in pO₂ ≈ 10 mmHg.