Table 2.
Membrane capacitance (Cm) and activation Boltzmann parameters of INa, ICa,T, ICa,L and If currents in the cardiomyocytes grown for 24 and 48 hrs in the absence or the presence of RLX
| Currents | Parameters | −RLX (24 hrs) | +RLX (24 hrs) | −RLX (48 hrs) | +RLX (48 hrs) |
|---|---|---|---|---|---|
| Cm (pF) | 58 6 5 | 75 6 8** | 9568 §§§ | 118 6 12** §§§ | |
| INa | Ip (pA/pF) | 325 6 30 | 500 6 55** | 400642§§ | 620 6 61** §§§ |
| Gm (nS/pF) | 4.5 6 0.3 | 8.1 6 0.6 ** | 5.160.4 § | 9.8 6 0.9** §§ | |
| Va (mV) | −26.1 6 2.1 | −27.2 6 2.8 | −27.562.7 | −30.3 6 3.1* § | |
| Ka (mV) | 6.4 6 0.4 | 6.2 6 0.4 * | 6.2 6 0.4 | 5.7 6 0.4* § | |
| Vr (mV) | 47.4 6 4 | 47.0 6 4 | 48.6 6 4 | 47.1 6 5 | |
| ICa,T | Ip (pA/pF) | 2.0 6 0.2 | 2.960.3*** | 2.4 6 0.2 § | 3.5 6 0.3*** §§ |
| Gm (pS/pF) | 20.1 6 2.1 | 30.1 6 2.4 ** | 20.3 6 2.1 | 40.2 6 3.3*** §§ | |
| Va (mV) | −37.0 6 3.6 | −36.76 3.8 | −36.563.2 | −37.2 6 4.2 | |
| Ka (mV) | 7.1 6 0.5 | 6.96 0.5 | 6.960.5 | 6.6 6 0.5 | |
| Vr (mV) | 68.4 6 5 | 67.1 6 4 6 | 69.1 6 4 | 67.7 6 4 | |
| ICa,L | Ip (pA/pF) | 8.1 6 0.8 | 16 6 1.2** | 1160.9 §§ | 2561.6** §§§ |
| Gm (pS/pF) | 100 6 10.3 | 159.7 6 15.5 ** | 150.2 6 12.2§§§ | 251.3 6 20.2*** §§§ | |
| Va (mV) | −11.8 6 1.1 | −13.2 6 1.2 | −13.261.2 § | −14.6 6 1.2* § | |
| Ka (mV) | 7.5 6 0.6 | 6.9 6 0.5 * | 7.1 6 0.6 | 5.9 6 0.5** §§ | |
| Vr (mV) | 69.4 6 5 | 67.4 6 4 | 68.1 6 4 | 69.1 6 4 | |
| Ito | Ito,50 (pA/pF) | 5.6 6 0.5 | 8.3 6 0.7** | 7.1 6 0.6 §§ | 11 6 0.9** §§ |
| IK1 | IK1,-120 (pA/pF) | 7.5 6 0.6 | 9.5 6 0.8** | 11.460.9 §§ | 13.5 6 1.1** §§§ |
| If | If,-150 (pA/pF) | 5.0 6 0.3 | 5.5 6 0.3* | 6.860.5 §§ | 8.1 6 0.6** §§§ |
| Gm (pS/pF) | 33.6 6 3.5 | 38.5 6 4.2 * | 46.2 6 3.8 §§ | 55.4 6 4.4** §§§ | |
| Va (mV) | −93.1 6 9.3 | −92.2 6 9.4 | −92.2 6 8.4 | −92.2 6 8.4 | |
| Ka (mV) | 16.4 6 0.3 | 16.1 6 0.4 | 16.1 6 0.4 | 15.6 6 0.4 |
Ip: data of the peak current at the voltage eliciting the maximal current; Ito: data at 50 mV; IK1: data at −120 mV; If: data at −150 mV; ICa,T evaluated in the presence of nifedipine, and ICa,L evaluated after detracting ICa,T from the total Ca2+ current (ICa,tot, see also Fig. 7D). Significance of differences (one-way ANOVA): −RLX versus +RLX, *P ‘ 0.05, **P ‘ 0.01, ***P ‘ 0.001; 24 hrs versus 48 hrs, §P ‘ 0.05, §§P ‘ 0.01, §§§P ‘ 0.001. Data are mean 6 S.E.M. of the values from 26 to 35 cardiomyocytes.