Figure 1. Inhibitory effect of ASIC and TRPV1 inhibitors on extracellular acid solution-induced [Ca²⁺]_i elevation in cultured rat ventricular cardiomyocytes.

(a) Representative [Ca²⁺]_i responses and quantitative analysis of normalized Fura-2/AM fluorescence induced by pH 6.0 (n = 15 cells) and pH 5.0 (n = 19 cells) solutions. Data were expressed as mean ± s.e.m (**P < 0.01 vs pH 6.0, Student’s t-test). Pretreatment with (b) Amiloride (300 μM, n = 12 cells), (c) PcTx1 (10 nM, n = 12 cells, left), (d) Ruthenium red (10 μM, n = 16 cells) or (e) Amiloride + ruthenium red (n = 10 cells) for 5 min all inhibited [Ca²⁺]_i elevation. Data were shown as mean ± s.e.m. **P < 0.01 vs control (Student’s t-test). RR, ruthenium red. (f) Representative [Ca²⁺]_i responses and quantitative analysis of normalized Fura-2/AM fluorescence induced by pH 5.0 solutions (n = 20 cells, control), pretreatment with CPZ (10 μM, n = 17 cells) and CPZ + PcTx1 (10 nM, n = 23 cells) for 5 min. Data were shown as mean ± s.e.m. **P < 0.01 vs control (ANOAN followed by LSD).