Table 1.
Properties of TG neurons
Type I | Type II | Type III | Type IV | |
---|---|---|---|---|
No. of cells | 10 | 66 | 6 | 5 |
Cell diameter, μM | 32.3 ± 7.2 | 30.2 ± 4.8 | 40.9 ± 4.9 | 34.9 ± 4.9 |
Cell capacitance, pF | 37.9 ± 21.6 | 30.3 ± 19.1 | 68.1 ± 29.9 | 46.4 ± 20 |
AP amplitude, mV | 113.2 ± 14.6 | 116.9 ± 0.8 | 114.6 ± 14.3 | 127.8 ± 10.5 |
Threshold, mV | −11.6 ± 5.8 | −13.2 ± 7.0 | −27.0 ± 7.4 | −17.6 ± 6.9 |
APD 50%, ms | 5.8 ± 1.4 | 2.6 ± 0.8 | 0.8 ± 0.2 | 1.9 ± 1.2 |
Max rate of depolarization, mV/s | 136.6 ± 109.5 | 163.9 ± 78.4 | 377.1 ± 141.1 | 283.9 ± 74.4 |
Max rate of repolarization, mV/s | 24.6 ± 11.6 | 53.0 ± 9.8 | 155.8 ± 57.3 | 94.4 ± 59.4 |
Percent capsaicin-sensitive cells | 60 | 76 | 0 | 0 |
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Action potentials (APs) were classified following many of the characteristics outlined in Cardenas et al. (1995). The APs were analyzed at the smallest value of injected current in which their parameters did not markedly change. The AP amplitude was measured from the baseline (−60 mV) to the peak; the AP duration at half height (APD 50%) is the time corresponding to half the action potential amplitude. TG, trigeminal ganglion.