Table 5.
Currents during 6.5 mV sec−1 ramp in VM and P cells
| n 15, Param | VM cells | P cells | Δ (mV or %) |
|---|---|---|---|
| Vh (mV) | −80.6 ± 0.6 | −81.3 ± 0.9 | −0.7 mV |
| IK1 peak (pA) | 965 ± 124 | 465 ± 57* | +107.5% |
| IK1 peak (mV) | −44.2 ± 1.7 | −50.1 ± 1.2* | 5.9 mV |
| INS (pA) | −218 ± 31 (14/15) | −45.6 ± 12.0* (10/15) | +379.3% |
| INS peak (mV) | −3.9 ± 3.1 | −23.2 ± 5.1* | 19.3 mV |
| ICa start (mV) | −11.6 ± 5.2 | −4.4 ± 3.0 | −7.2 mV |
| ICa (pA) | −39.9 ± 17.5 (6/15) | −20.1 ± 9.6 (4/15) | +98.5% |
| ICa peak (mV) | −5.1 ± 4.7 | −10.5 ± 7.2 | 5.4 mV |
| Δ (pA) | −51.9 ± 6.9 (15/15) | −29.8 ± 9.3 (7/15) | +74.1% |
| Ito start (mV) | 0.64 ± 2.1 | −19.2 ± 3.7* | 19.8 mV |
| Ito (pA) | 109 ± 14 | 436 ± 62* | −75% |
| Iramp peak−Ih (pA) | 812 ± 114 | 863 ± 71 | −5.9% |
| Irepol (pA) | 64.7 ± 10.8 | 396.4 ± 62.2* | −83.6% |
| Irepol peak (mV) | 8.8 ± 2.6 | −15.9 ± 4.6* | 24.7 mV |
| IPS start (mV) | 8.9 ± 2.6 | −5.6 ± 2.7* | 14.5 mV |
| IPS peak (pA) | 197.0 ± 28.4 (15/15) | 36.0 ± 19.0* (5/15) | +447.2% |
| IPS peak (mV) | −44.4 ± 1.6 | −52.1 ± 1.8 | 7.7 mV |
| IPS peak−Ih (pA) | 981 ± 124 | 428 ± 68* | +53.3% |
n 15, 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; 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; Δ (pA), difference in pA between ICa peak during depolarization and minimum outward current preceding the beginning of IPS on repolarization; 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 peak (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 INS peak and Ih; Vh (mV), holding potential in mV; Param, parameters measured; VM cells, data from ventricular myocardial cells; P cells, data from Purkinje cells; *statistically significant difference between P and VM cells data.