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. 2012 Sep 17;590(Pt 23):6093–6108. doi: 10.1113/jphysiol.2012.236117

Figure 1. Effects of isoproterenol on intracellular Ca2+ handling.

Figure 1

A, example cytosolic Ca2+ transients measured with indo-1 (0.75 Hz, electrical stimuli marked by arrows) followed by rest under control conditions ([Ca2+]o= 2 mm) and in the presence of 1 μm ISO. Control resting [Ca2+]i level is marked by dashed line. Note spontaneous Ca2+ wave that occurred during the rest period in the presence of ISO (star). B, example [Ca2+]i increases in response to 10 mm caffeine (black bars) used to assess SR Ca2+ content. Caffeine was applied immediately after identical 0.75 Hz pacing trains as shown in A, prior to the occurrence of spontaneous Ca2+ waves. Summary data of Ca2+ transient amplitude (0.75 Hz; C), resting [Ca2+]i (D) and SR Ca2+ load (E) under control conditions, in the presence of ISO, and in the presence of ISO with 7.5 μm cyclopiazonic acid (CPA) in 100 μm[Ca2+]o. *P < 0.05 versus control.