Elevation of Orai1-mediated SOCE activity and SR Ca<sup>2+</sup> store overload in adult <i>mdx</i> muscles.

<p>(<b>A</b>) Representative trace of Mn<sup>2+</sup> quenching of Fura-2 fluorescence at 360 nm (F<sub>360</sub>) wavelength. Lines and arrows designate perfusion of muscle fiber by 20 mM caffeine plus 5 uM ryanodine, MnCl<sub>2</sub> and TritonX-100. Upper panel: black trace is FDB fiber from <i>wt</i> mice transfected with empty vector (control WT) and grey trace is with shOrai1 (Orai1KD WT); lower panel: black trace is FDB fiber from <i>mdx</i> mice transfected with empty vector (Control <i>mdx</i>) and grey trace is with Orai1 (Orai1KD <i>mdx</i>). (<b>B</b>) Statistical summarization of the data in (A), n = 11–19, <sup>*</sup><i>P</i><0.05 compared to Control WT; <sup>#</sup><i>P</i><0.05 compared to Control <i>mdx</i>. (<b>C</b>) Statistical results of resting intracellular Ca<sup>2+</sup> levels in Control WT (open bar), Orai1KD WT (black bar), Control <i>mdx</i> (hatched bar) and Orai1KD <i>mdx</i> (black bar). (<b>D</b>) Statistical results of caffeine-sensitive SR Ca<sup>2+</sup> store in the four groups. n = 11–19, <sup>*</sup><i>P</i><0.05 compared to Control WT; <sup>#</sup><i>P</i><0.05 compared to Control <i>mdx</i>.</p>