Expression and Impact of Adenosine A3 Receptors on Calcium Homeostasis in Human Right Atrium

Figures

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  Figure 1. Adenosine receptor mRNA expression in human right atrial tissue samples from seven patients.

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  Figure 2. Impact of A3R inhibition on calcium homeostasis at baseline. (A) ITI frequency; (B) SR calcium load; (C) ICa density; (D) tau of ICa. Data were recorded in nine myocytes from eight patients before (blue) and after perfusion of myocytes with MRS1191 (purple). Significant differences are indicated with * p < 0.05 (paired t-test).

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  Figure 3. Impact of crosstalk between A3R and A2AR on SR calcium homeostasis. (A) ITI frequency; (B) SR calcium load; (C) relationship between ITI frequency and SR calcium load. Data were recorded in 21 myocytes from 19 patients before (blue) and after perfusion of myocytes with CGS21680 (yellow) and CGS21680 and MRS1191 (orange); (D) RyR2 s2808 phosphorylation in 106 myocytes from 19 patients. Significant differences between the control and treatments are indicated with * p < 0.05; *** p < 0.001, ‡ p < 0.01 for CGS21680 + MRS1191 vs. CGS21680. Data in (A,B) were analyzed using ANOVA with Welch’s correction (p-values are given above the bars) and Games–Howell post-test. Unpaired t-test was used in panel (D).

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  Figure 4. Impact of the crosstalk between A3R and A2AR on calcium sparks. (A) Calcium spark recordings (colored traces) from their respective spark sites (colored circles) in a patient before and after exposure to 200 nM CGS21680 + 1 μM MRS1191; (B) spark density (sparks/s/1000 μm2). Sparks were recorded in 10 patients before (blue) and after perfusion of myocytes with CGS21680 (yellow) and CGS21680 and MRS1191 (orange). Number of cells are given below bars; (C) spark amplitude (dF/F0); (D) spark full width at half maximum (FWHM, μm); (E) tau for spark decay (ms). Significant differences between the control and treatments are indicated with* p < 0.05; ** p < 0.01; *** p < 0.001. Data were analyzed using Kruskal–Wallis (p-values are given above Bars) and Dunn’s post-test in (B) and ANOVA with Welch’s correction in panel (C–E). Number of cells with sparks are given below the bars in panel (C–E).

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  Figure 5. Impact of the crosstalk between A3R and A2AR on L-type calcium current. (A) ICa density; (B) fast time constant, tau, for ICa decay; (C) correlation between tau and ITI frequency (from Figure 3A); (D,E) correlation between tau and ICa density before and after transient exposure to 10 mM caffeine. Currents were recorded in 19 patients before (blue) and after perfusion of myocytes with CGS21680 (yellow) and CGS21680 + MRS1191 (orange). Statistical significance was evaluated using Pearson’s product-moment correlation; (F) Time constant, tau, for the decay of the first ICa after transient exposure to caffeine. Significant differences between control and treatments are indicated with; *** p < 0.001, ‡ p < 0.01 for CGS21680 + MRS1191 vs. CGS21680. Data were analyzed using ANOVA (p-values are given above the bars) and Tukey’s post-test in (A,B,F). Number of cells are given below bars.