Table 1.
Action potential characteristics of juvenile and adult wild type and mXinα−/− ventricular myocytes
| Juvenile (3~4-week-old) | Adult (10~20-week-old) | |||
|---|---|---|---|---|
| mXinα+/+ | mXinα−/− | mXinα+/+ | mXinα−/− | |
| Cm, pF | 75.5±2.7 (n=47) | 72.6±3.5 (n=58) | 102.2±4.6 (n=113) | 134.3±5.6* (n=104) |
| MDP, −mV | 70.5±1.4 (n=15) | 70.2±1.1 (n=17) | 77.0±1.4 (n=17) | 60.2±2.5* (n=10) |
| APA, mV | 85.9±4.9 (n=15) | 81.7±1.1 (n=17) | 91.9±2.9 (n=17) | 83.3±3.0 (n=10) |
| APD20, ms | 3.1±0.1 (n=15) | 4.1±1.0* (n=17) | 5.9±0.8 (n=17) | 9.2±1.6# (n=10) |
| APD50, ms | 9.0±0.6 (n=15) | 11.6±2.9* (n=17) | 20.0±4.2 (n=17) | 34.5±7.8 (n=10) |
| APD90, ms | 37.1±2.7 (n=15) | 46.8±3.5* (n=17) | 167.4±8.4 (n=17) | 213.6±31.0 (n=10) |
The cardiomyocytes were driven electrically at 1 Hz. Cm, membrane capacitance; MDP, maximum diastolic potential; APA, action potential amplitude; APD20, APD50 and APD90, action potential duration at 20%, 50% and 90% repolarization levels, respectively. Values are mean±SEM. Number in parenthesis, number of ventricular myocytes tested;
*
p<0.05, significantly different from wild type control values by Student’s t test or
#
p<0.05 by Mann-Whitney Rank Sum test.