Thresholds for the activation of neurons by mechanical and electrical stimulation of the dura
| von Frey (g) | A-δ (mA) | C-fiber (mA) | |
|---|---|---|---|
| Vehicle | 4.6 ± 0.5 (42) | 3.6 ± 0.3 (21) | 3.4 ± 0.8 (5) |
| Morphine | 2.7 ± 0.4** (37) | 2.1 ± 0.3** (30) | 2.3 ± 0.4 (9) |
↵Data are represented as mean ± SEM. The numbers in parentheses indicate the number of neurons for each treatment group in which thresholds were determined. **p < 0.01 compared to vehicle-treated animals (Student's t test).