Table 2.
Effects of CNP (0.3 μM) on Cai2+ transients and contractile parameters of isolated cardiomyocytes
| Cai2+ transients | WT | PKG ITG |
|---|---|---|
| Baseline | ||
| Diastolic ratio (405/495 nm) | 1.43±0.02 | 1.43±0.02 |
| Cai2+ peak amplitude | 0.17±0.01 | 0.17±0.01 |
| Time to 50% decay (ms) | 141.0±10.8 | 153.4±21.4 |
| CNP | ||
| Diastolic ratio (405/495 nm) | 1.42±0.03 | 1.44±0.02 |
| Cai2+ peak amplitude | 0.22±0.03* | 0.28±0.03*§ |
| Time to 50% decay (ms) | 106.7±11.3* | 79±7.8*§ |
| Contractile parameters | ||
| Baseline | ||
| Lmax (μm) | 107.1±5.3 | 117.5±6.5 |
| Lmin (μm) | 104.7±5.4 | 113.4±6.5 |
| Cell shortening (%) | 2.29±0.3 | 3.3±0.6 |
| Time to 90% relaxation (ms) | 464±76 | 465±63 |
| CNP | ||
| Lmax (μm) | 106.0±5.5 | 115.2±7.2 |
| Lmin (μm) | 102.2±5.6 | 104.1±7.7 |
| Cell shortening (%) | 3.88±0.7* | 9.7±1.58*§ |
| Time to 90% relaxation (ms) | 217±34* | 124±13*§ |
Indo-1 signals were determined in isolated ventricular cardiomyocytes from WT and PKG ITG mice. The contractile measurements were performed by edge detection. Isolated myocytes were paced at 0.5 Hz. Lmax indicates the maximal myocyte length, and Lmin the minimal myocyte length. The maximal magnitude of contraction was normalized to Lmax and expressed as percentage of shortening. Values represent the mean±s.e.m. (n=13 cells from each of eight mice per genotype).
*
P<0.05 vs baseline,
§
P<0.05 vs WT.