Table 2.
Comparison of parameters of activation of Ih in the four main classes of rat and mouse HCN1+/+ DRG neurons
| Large | Medium fast | Medium slow | Small | |||||
|---|---|---|---|---|---|---|---|---|
| Rat | Mouse | Rat | Mouse | Rat | Mouse | Rat | Mouse | |
| Size classes (μm) | > 35 | > 30 | 25–35 | 20–30 | 25–35 | 20–30 | < 25 | < 20 |
| V½ (mV) | −81.6 ± 1.6 | −84.3 ± 2.4 | −81.1 ± 1.6 | −86.7 ± 2.4 | −85.9 ± 1.0 | −91.4 ± 1.9 | −86.3 ± 1.6 | −88.3 ± 1.4 |
| τf (ms, at −90 mV) | 155 ± 17 | 101 ± 28 | 200 ± 56 | 178 ± 38 | 622 ± 90 | 652 ± 68 | 943 ± 80 | 830 ± 87 |
| τs (ms, at −90 mV) | 526 ± 72 | 443 ± 39 | 929 ± 109 | 727 ± 71 | 1378 ± 128 | 1352 ± 125 | 2146 ± 235 | 1616 ± 107 |
| ΔV½ (mV) FK | 0.2 ± 0.5 | 1.3 ± 0.9 | 1.9 ± 0.6 | 0.9 ± 0.5 | 14.4 ± 0.7 | 13.2 ± 1.9 | 13.8 ± 0.4 | 16.7 ± 0.5 |
All data from Cs-subtracted current traces. The value of V½ was almost unaffected by forskolin (FK, 50 μm) in large and medium fast neurons, but was shifted in the positive direction by ∼14 mV in both medium slow and small neurons (see also Fig. 6E). Similar results were also obtained in rat neurons with exposure to PGE2 (10 μm) and with cAMP (50 μm) incorporated into the patch-clamp pipette. Number of neurons n = 10–15 for each measurement.