Table 2.
Contribution of ENDO/EPI differences in individual ionic currents to differences in action potential, Ca2+ transient, and contraction between the ENDO/EPI cellular models
| Ionic current | RP | APD10 | APD50 | APD90 | CaT70 | CaT90 | T max | TR75 |
|---|---|---|---|---|---|---|---|---|
| i pNa | 0.99 | 1.08 | 1.08 | 1.08 | 1.00 | 0.97 | 1.08 | 1.13 |
| i Kr | 0.99 | 1.06 | 1.06 | 1.06 | 1.00 | 0.97 | 1.07 | 1.13 |
| i Ks | 0.99 | 1.21 | 1.18 | 1.17 | 1.00 | 0.97 | 1.09 | 1.19 |
| i CaL | 0.99 | 1.35 | 1.13 | 1.11 | 1.00 | 0.97 | 1.13 | 1.22 |
| i bCa | 1.00 | 1.05 | 1.05 | 1.05 | 1.00 | 0.97 | 1.08 | 1.13 |
| i NaK / i NaCa | 0.99 | 1.20 | 1.11 | 1.10 | 1.00 | 0.97 | 1.03 | 1.08 |
| Total | 0.99 | 1.31 | 1.26 | 1.25 | 1.00 | 0.97 | 1.06 | 1.14 |
The ENDO/EPI ratio between the characteristics produced by the models at isometric twitches is shown
RP resting membrane potential; APD 10,50,90 action potential duration at 10, 50 and 90% repolarization, respectively; CaT 70,90 calcium transient duration at 70 and 90% decay, respectively; T max time to peak contraction; TR 75 time to 75% relaxation (measured as the time interval from T max to the time of 75% relaxation)