Table 8.
Currents during the 1040 mV sec−1 ramp in VM and P cells
| n 17, Param | VM cells | P cells | Δ (mV or %) |
|---|---|---|---|
| Vh (mV) | −80.6 ± 0.5 | −81.8 ± 0.9 | 1.2 mV |
| IK1 peak (pA) | 1082 ± 113 | 614 ± 60* | +76.2% |
| IK1 peak (mV) | −52.2 ± 0.7 | −58.0 ± 0.7* | 5.8 mV |
| INS (pA) | −405 ± 57 | −710 ± 74* | −42.9% |
| INS peak (mV) | −16.2 ± 2.6 | −19.8 ± 1.4 | 3.6 mV |
| INa3 (pA) | −1986 ± 132 | −1645 ± 199 | +20.7% |
| INa1 Th (mV) | −38.3 ± 1.1 | −47.1 ± 0.9* | 8.8 mV |
| INa1 (pA) | −9197 ± 393 (17/17) | −9491 ± 280 (16/17) | −3.09% |
| End INa1 (pA) | 863 ± 105 (17/17) | 351 ± 69* (16/17) | +145.8% |
| End INa1 (mV) | −27.9 ± 1.5 | −30.8 ± 4.4 | 2.9 mV |
| ICa start (mV) | −0.6 ± 1.7 | −8.0 ± 0.0 | 7.2 mV |
| ICa (pA) | −111.6 ± 28.6 (14/17) | −19.5 ± 18.0* (2/17) | +472% |
| ICa peak (mV) | 20.9 ± 1.1 | −4.0 ± 1* | 24.9 mV |
| Ito start (mV) | 14.0 ± 4.0 | −14.1 ± 3.25* | 28.1 mV |
| Ito (pA) | 222 ± 28 | 1776 ± 187* | −87.5% |
| Iramp peak−Ih (pA) | 884 ± 85 | 1658 ± 172 | −46.6% |
| Irepol (pA) | 396 ± 50 | 1522 ± 158* | −73.9% |
| Irepol peak (mV) | 10 ± 3.3 | −16.7 ± 2.0* | 26.7 mV |
| IPS start (mV) | 5.4 ± 3.6 | −18.9 ± 1.9* | 24.3 mV |
| IPS (pA) | 223 ± 40 | 163 ± 24 (15/17) | +36.8% |
| IPS peak (mV) | −47.2 ± 1.7 | −50.4 ± 1.0 | 3.2 mV |
| IPS peak−Ih (pA) | 733 ± 100 | 244 ± 47* | +200.4% |
n, number of cells studied; Δ (mV or%), difference in mV or percent of VM cells data with respect to P cells data; IK1 peak (pA), amplitude of IK1 peak in pA, measured as the difference from Ih; IK1 peak (mV), voltage in mV at which IK1 peaked; INS (pA), current amplitude in pA during the negative slope region; INS, peak (mV), voltage in mV of INS peak; INa1 Th (mV), voltage at which INa1 began; INa1 (pA), amplitude in pA of INa1; ICa start (mV), beginning of ICa component in mV determined as the departure of current trace from INS peak; ICa (pA), amplitude of ICa component in pA as the difference between its beginning and its peak; ICa peak (mV), peak in mV of ICa; Ito, start (mV), voltage in mV at which the increasing outward current started at INS or ICa peaks; Ito (pA), amplitude of outward current in pA measured between its beginning and ramp peak; Iramp peak−Ih (pA), outward current at ramp peak measured as difference from Ih; Irepol (pA), amplitude in pA of the outward current between ramp peak and its smallest value prior to the beginning of IPS; Irepol peak (mV), voltage in mV at which the outward current was smallest prior to INS beginning; IPS start (mV), voltage in mV at which IPS began; IPS (pA), current in pA at IPS peak, measured as difference between its beginning and its peak; IPS peak (mV), voltage in mV at which PS region peaked; IPS peak−Ih (pA), current in pA measured as difference between IPS peak and Ih; End INa1 (pA), Amplitude in pA of the current at the end of INa1 inactivation; End INa1 (mV), voltage in mV of the current at the end of INa1 inactivation; Vh (mV), holding potential in mV; Param, parameters measured; VM cells, data from ventricular myocardial cells; P cells, data from Purkinje cells; INa3 (pA), amplitude in pA of INa3 measured as the difference between its peak and the end of the step; Numbers in parenthesis (e.g., 17/17), number of cells in which the parameter was present over the total number of cells studied; *statistically significant difference between P and VM cells data. Other explanations as in the legend of Table 7.