TABLE 1.
Fundamental properties of slow and fast fibers and of cardiac trabeculae, in the absence or presence of 20, 50 and 100 µM RPI-194.
| Slow Fibers | Fast Fibers | Cardiac Trabeculae | |
|---|---|---|---|
| pCa50, series A, N = 24 of each | 6.28 ± 0.03 (6.10–6.58) | 6.27 ± 0.02 (6.03–6.46) | 5.68 ± 0.01 (5.49–5.80) |
| ∆pCa50 with 0 µM RPI-194 (series B), N = 6 of each | −0.01 ± 0.02 (−0.04–0.01) | 0.04 ± 0.02 (−0.01–0.06) | 0.00 ± 0.01 (−0.01–0.01) |
| ∆pCa50 with 20 µM RPI-194 (series B), N = 6 of each | 0.14 ± 0.02 (0.10–0.24) | 0.04 ± 0.02 (−0.01–0.12) | 0.03 ± 0.02 (−0.01–0.10) |
| ∆pCa50 with 50 µM RPI-194 (series B), N = 6 of each | 0.35 ± 0.02 (0.30–0.42) | 0.14 ± 0.02 (0.07–0.19) | 0.16 ± 0.02 (0.09–0.20) |
| ∆pCa50 with 100 µM RPI-194 (series B), N = 6 of each | 0.71 ± 0.05 (0.58–0.84) | 0.25 ± 0.02 (0.14–0.27) | 0.28 ± 0.02 (0.21–0.32) |
| Vo (FL/s), in the absence of RPI-194 (series A), N = 24 of each a | 1.35 ± 0.04 (1.04–1.68) | 4.53 ± 0.17 (3.19–6.31) | — |
| Vo ratio with 0 µM RPI-194 (series B/series A), N = 6 of each | 0.94 ± 0.07 (0.83–1.02) | 0.89 ± 0.04 (0.68–1.00) | — |
| Vo ratio with 20 µM RPI-194 (series B/series A), N = 6 of each | 0.75 ± 0.03 (0.69–0.86) | 0.67 ± 0.06 (0.51–0.82) | — |
| Vo ratio with 50 µM RPI-194 (series B/series A), N = 6 of each a | 0.58 ± 0.04 (0.51–0.68) | 0.61 ± 0.06 (0.49–0.85) | — |
| Vo ratio with 100 µM RPI-194 (series B/series A), N = 6 of each | 0.50 ± 0.01 (0.48–0.52) | 0.52 ± 0.04 (0.42–0.64) | — |
a
Values are mean ± SEM (range in parentheses). Here, Vo = maximal shortening velocity.