Table 1.
Maturation of membrane, action potential, potassium current and sodium current properties.
| E10–E12 | E14–E16 | E19–E21 | ANOVA P | |
|---|---|---|---|---|
| Membrane properties | ||||
| RMP (mV) | −62.21 ± 10.31 (22) | −66.33 ± 6.87 (21) | −66.52 ± 8.49 (28) | P = 0.17 (Figure 1D) |
| Time constant tau (ms) | 15.57 ± 6.23 (10) | 5.90 ± 3.26 (13) | 3.18 ± 1.33 (20) | P < 0.0001 (Figure 5B) |
| Input resistance (MΩ) | 324.60 ± 120.30 (10) | 211.40 ± 49.87 (13) | 123.90 ± 49.90 (20) | P < 0.0001 (Figure 5C) |
| Cell capacitance (pF) | 47.91 ± 4.61 (10) | 26.78 ± 9.97 (13) | 26.15 ± 4.60 (20) | P < 0.0001 (Figure 5D) |
| Action potential (AP) properties | ||||
| Threshold current (pA) | 121.30 ± 80.30 (22) | 242.70 ± 68.58 (21) | 321.70 ± 121.00 (28) | P < 0.0001 (Figure 1B) |
| Latency (ms) | 19.49 ± 10.86 (22) | 4.17 ± 1.15 (21) | 3.00 ± 0.57 (28) | P < 0.0001 (Figure 2C) |
| Max rise rate (mV/ms) | 38.59 ± 12.13 (22) | 98.76 ± 40.98 (21) | 155.60 ± 42.19 (28) | P < 0.0001 (Figure 2E) |
| Max fall rate (mV/ms) | −19.26 ± 5.78 (22) | −56.30 ± 25.85 (21) | −104.40 ± 29.79 (28) | P < 0.0001 (Figure 2F) |
| AP half width (ms) | 4.57 ± 1.07 (21) | 1.91 ± 0.93 (21) | 0.97 ± 0.17 (28) | P < 0.0001 (Figure 2D) |
| AP reliability range (ms) | 8.89 ± 8.98 (22) | 0.44 ± 0.24 (21) | 0.21 ± 0.14 (28) | P < 0.0001 (Figure 3C) |
| AP height (mV)§ | 69.09 ± 11.64 (22) | 80.27 ± 8.83 (21) | 82.94 ± 9.97 (28) | P < 0.0001 |
| KV current (Ik) | ||||
| Total Ik at +20 mV (pA) | 3076 ± 1272 (35) | 4386 ± 1105 (42) | 6240 ± 1327 (39) | P < 0.0001 (Figure 6B) |
| Total Ik conductance (nS) | 26.99 ± 11.16 (35) | 38.47 ± 9.70 (42) | 54.74 ± 11.64 (39) | P < 0.0001 (Figure 6C) |
| Total Ik density (pA/pF) | 71.71 ± 26.75 (10) | 172.00 ± 65.47 (13) | 258.60 ± 65.62 (15) | P < 0.0001 (Figure 6D) |
| NaV current (INa) | ||||
| V25% (mV)∧ | −33.64 ± 4.99 (14) | −40.50 ± 5.57 (24) | −50.36 ± 6.02 (11) | P < 0.0001 |
| INa (pA)* | −1728.00 ± 759.10 (14) | −2453.00 ± 654.00 (24) | −3386.00 ± 1089.00 (11) | P < 0.0001 (Figure 10B) |
| INa conductance (nS)* | 24.15 ± 8.90 (14) | 32.43 ± 7.51 (24) | 44.97 ± 12.07 (11) | P < 0.0001 (Figure 11C) |
| INa density (pA/pF)* | −36.17 ± 13.99 (12) | −84.16 ± 48.52 (20) | −98.59 ± 53.48 (10) | P < 0.01 (Figure 11D) |
| Max rise rate (pA/ms)* | −4223.00 ± 2906.00 (14) | −7836.00 ± 3837.00 (24) | −10546.00 ± 5736.00 (11) | P < 0.01 (Figure 10C) |
| Max fall rate (pA/ms)* | 1008.00 ± 735.00 (14) | 1842.00 ± 776.80 (24) | 2782.00 ± 1117.00 (11) | P < 0.0001 (Figure 10D) |
| Half width (ms)* | 1.99 ± 1.03 (14) | 1.29 ± 0.37 (24) | 1.13 ± 0.14 (11) | P < 0.01 (Figure 10E) |
| Reliability range (ms)* | 0.46 ± 0.42 (22) | 0.39 ± 0.39 (23) | 0.50 ± 0.42 (18) | P = 0.69 (Figure 10F) |
| V1/2 (mV) | −49.87 ± 3.20 (7) | −47.13 ± 5.27 (8) | −54.67 ± 3.77 (7) | P < 0.01 (Figure 11F) |
RMP, Resting membrane potential. §Peak AP amplitude measured relative to the RMP. ∧Holding voltage 25% above activation voltage. *Measured at V25% for each developmental age.