Intracellular Ca2+-Mediated Mechanisms for the Pacemaker Depolarization of the Mouse and Guinea Pig Sinus Node Tissue

Figures

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  Figure 1. Effects of BAPTA and ryanodine on the sinus node action potential of the mouse and guinea pig. Typical traces before (black lines) and after (red lines) application of 300 μM BAPTA (upper) and 0.1 μM ryanodine (lower).

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  Figure 2. Effect of SEA0400 on the sinus node action potential of the mouse and guinea pig. Typical traces before (black lines) and after (red lines) application of 1 μM (upper) and 10 μM (lower).

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  Figure 3. Effect of low Na+ solution on the sinus node action potential of the mouse and guinea pig. Typical traces before (black lines) and after (red lines) rapid change of the extracellular solution to low Na+ solution.

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  Figure 4. Effect of niflumic acid on the sinus node action potential of the mouse and guinea pig. Typical traces before (black lines) and after (red lines) application of 30 μM niflumic acid.

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  Figure 5. Effect of SEA0400 on spontaneously occurring Ca2+ transients in the mouse sinus node tissue. (A) Typical x-y images of the myocardium loaded with Cal-590 before (a–c) and 10 min after the addition of 1μM SEA0400 (d–f). Panels c and f are the images at the peak of the Ca2+ transient. Note that Ca2+ oscillations were observed during the interval between the Ca2+ transients (arrows). (B) Time course of the changes in fluorescence before addition (a–c) and 10 min after the addition of 1 μM SEA0400 (d–f). Time course of the fluorescence intensity quantified in the whole field of view (a,d), cell 1 (b,e), and cell 2 (c,f) as shown in panel (A)/(c).

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  Figure 6. Effect of SEA0400 on spontaneously occurring Ca2+ transients in the guinea pig sinus node tissue. (A) Typical x-y images of the myocardium loaded with Cal-590 before (a–c) and 10 min after the addition of 1μM SEA0400 (d–f). Panels c and f are the images at the peak of the Ca2+ transient. Note that no Ca2+ oscillation was observed during the interval between the Ca2+ transients (a,b,d,e). (B) Time course of the changes in fluorescence before addition (a–c) and 10 min after the addition of 1 μM SEA0400 (d–f). Time course of the fluorescence intensity quantified in the whole field of view (a,d), cell 1 (b,e), and cell 2 (c,f) as shown in panel (A)/(c).