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. 2020 Apr 14;152(7):e201912511. doi: 10.1085/jgp.201912511

Figure 14.

Figure 14.

Replacing Ca2+ by Mg2+ improved the maximum rate of action potential depolarization in wild type soleus and HyperKPP soleus. Resting EM values were divided in bins of 5 mV and mean resting EM and maximum rate of depolarization were averaged. Lines were drawn from a sigmoidal nonlinear regression analysis (except for the 5.2 mM Mg2+ in A because a good fit could not be obtained). The inset in B is to illustrate the difference in the relationship at 0.3 mM Ca2+ between wild type and HyperKPP muscles. Horizontal and vertical bars represent the SE of 6–47 fibers/6 muscles. *, Mean maximum rate of depolarization significantly different from that at 2.4 mM Ca2+. †, Mean maximum rate of depolarization of HyperKPP soleus significantly different from that of wild type. ANOVA and LSD, P < 0.05.