Table 2.
Electrophysiological properties of motor neurons
| Wild type [mean ± SEM (n)] | SMA [mean ± SEM (n)] | MN-rescued SMA [mean ± SEM (n)] | |
|---|---|---|---|
| RMP (mV) | −57 ± 1 (12) | −56 ± 3 (6) | −56 ± 3 (7) |
| Capacitance (pF) | 224 ± 34 (12) | 176 ± 38 (7) | 212 ± 37 (7) |
| Input resistance (MΩ) | 62 ± 6 (12) | 75 ± 25 (7) | 51 ± 10 (7) |
| PIC amplitude (pA) | −106 ± 16 (12) | −244 ± 66 (7)* | −109 ± 52 (8)† |
| AP overshoot (mV) | 30.5 ± 2 (12) | 27.7 ± 5 (6) | 26.4 ± 2 (7) |
| AP duration (ms) | 1.29 ± 0.1 (12) | 1.32 ± 0.02 (6) | 1.46 ± 0.02 (7) |
| AP rate of rise (mV/ms) | 97 ± 9 (12) | 115 ± 17 (6) | 84 ± 9 (7) |
| V threshold (mV) | −33.9 ± 1.9 (12) | −41.5 ± 2.5 (6)* | −31.1 ± 2.5 (7)† |
| I-ON (pA) | 371 ± 86 (12) | 246 ± 122 (6) | 461 ± 137 (7) |
| I-OFF (pA) | 409 ± 136 (12) | 445 ± 90 (6) | 536 ± 126 (7) |
| Slope (Hz/nA) | 37 ± 8 (12) | 31 ± 8 (6) | 33 ± 9 (7) |
| Synaptic potentials (/s) | 3.3 ± 0.3 (12) | 12.4 ± 5.1 (5)* | 2.5 ± 0.6 (7)† |
Table values are mean ± SEM *p ≤ 0.05 relative to control;
†p ≤ 0.05 relative to SMA, one-way ANOVA with a Bonferroni post hoc analysis. Definitions: RMP, resting membrane potential; capacitance, whole cell capacitance; PIC amplitude, amplitude of the persistent inward current; AP overshoot, overshoot of the action potential (AP) past 0mV; AP duration, duration of the AP at half-peak; AP rate of rise, rate of rise of the action potential; V threshold, threshold of the cell for AP firing; I-ON, the amount of current needed to elicit AP firing during a ramp of depolarizing current; I-OFF, the level of depolarizing current at which firing ceases during the descending current ramp; slope, slope of the frequency—current relationship; synaptic potentials, frequency of post-synaptic potentials in MNs at rest.