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. Author manuscript; available in PMC: 2015 Nov 30.
Published in final edited form as: Circulation. 2012 Mar 28;125(17):2059–2070. doi: 10.1161/CIRCULATIONAHA.111.067306

Figure 3. Quantification of diastolic SR Ca2+-leak with tetracaine in voltage-clamped atrial myocytes from sinus rhythm (Ctl) and cAF patients.

Figure 3

A, Experimental protocol for determination of SR Ca2+-leak (Fluo-3). After steady-state stimulation for 1-minute at 0.5 Hz, the bath solution is rapidly switched to sodium- and calcium-free (0Na+, 0Ca2+) solution. Tetracaine (1-mmol/L) blocks RyR2, and the shift downward in resting [Ca2+]i is proportional to SR Ca2+-leak. After at least 30-seconds and tetracaine washout, SR Ca2+-content is measured with 10-mmol/L caffeine. B,C, Mean±SEM tetracaine-dependent decrease in resting [Ca2+]i (SR Ca2+-leak; B) and for SR Ca2+-leak normalized to SR Ca2+-content (C) in control myocytes and myocytes pretreated (30-minutes) with the CaMKII-inhibitor KN-93 (1-μmol/L), its inactive analogue KN-92 (1-μmol/L) and the PKA-inhibitor H-89 (1-μmol/L), respectively. *P<0.05 and **P<0.01 vs. corresponding means in Ctl. Numbers within columns indicate myocytes/patients. D,E, SR Ca2+-leak plotted vs. SR Ca2+-load. Curves are from exponential regression. *P<0.05 and ***P<0.001, respectively vs. corresponding rate constant in Ctl (F-test).