Fig. 7.
Resting sarcolemmal divalent cation permeability in myotubes. (A) Representative traces indicating the change in the rate of the Fura2 fluorescence that was quenched by Mn2+ in wild-type, heterozygous, and homozygous myotubes from RYR1-p.G2435R mice after changing from imaging buffer to manganese buffer. (B) Box plots showing the quench rate (median and interquartile range) in control, 25 μM gadolinium–treated, or 250 nM SAR7334–treated myotubes from each of the three genotypes. The whiskers represent the 10th to 90th percentile. A larger rate of quench is represented by a more negative number, and this indicates a greater cationic entry through the sarcolemmal cation channels into the cell from the extracellular space, which is an estimate of the sarcolemmal permeability to Ca2+. §P < 0.05 in RYR1-p.G2435R homozygous versusRYR1–p.G2435R heterozygous and wild-type mice. **P < 0.005 and ****P < 0.0001 in each genotype (Kruskal–Wallis test with Dunn’s multiple comparisons test, N ≥ 35 myotubes for each condition).