Table 6.
Effects of Lidocaine, Carbamazepine, and Amitriptyline on the Characteristics of the Response to a 30-second Pulse of CO2 Applied to the Receptive Field of Corneal Polymodal Nociceptors Recorded in Intact and Lesioned Corneas (24, 48, or 72 Hours After Lesion With Microkeratome)
| Intact Corneas | Lesioned Corneas | |||||
|---|---|---|---|---|---|---|
| Before | After | Wash | Before | After | Wash | |
| Lidocaine | ||||||
| Ongoing activity (imp/s) | 0.08 ± 0.05 | 0.09 ± 0.06 | 0.10 ± 0.09 | 0.27 ± 0.25 | 0 ± 0 | 0.08 ± 0.06 |
| Latency (s) | 13.4 ± 2.49 | 35.06 ± 7.89* | 19.89 ± 3.01 | 13.03 ± 2.38 | 44.9 ± 10.28* | 16.6 ± 4.03 |
| Activity during the pulse (imp/s) | 1.56 ± 0.38 | 0.29 ± 0.14† | 1.35 ± 0.30 | 2.82 ± 0.60 | 0.16 ± 0.13† | 2.10 ± 1.14 |
| Postdischarge (imp/s) | 0.82 ± 0.19 | 0.14 ± 0.08† | 0.68 ± 0.27 | 1.25 ± 0.72 | 0.14 ± 0.13 | 0.77 ± 0.47 |
| Total response duration (s) | 26.6 ± 3.38 | 5.72 ± 3.36† | 30.59 ± 3.98 | 28.89 ± 5.72 | 2.21 ± 3.34* | 19.67 ± 5.28 |
| Mean discharge rate (imp/s) | 3.22 ± 0.49 | 0.28 ± 0.15† | 2.84 ± 0.31 | 3.84 ± 0.48 | 0.64 ± 0.40† | 3.69 ± 0.97 |
| n | 12 | 6 | ||||
| Carbamazepine | ||||||
| Ongoing activity (imp/s) | 0.16 ± 0.16 | 0.17 ± 017 | 0 ± 0 | 0.02 ± 0.02 | 0.02 ± 0.02 | 0.08 ± 0.08 |
| Latency (s) | 14.24 ± 3.96 | 51.43 ± 8.57† | 27.96 ± 8.33 | 16.7 ± 4.25 | 24.65 ± 9.43 | 15.40 ± 3.65 |
| Activity during the pulse (imp/s) | 1.32 ± 0.40 | 0.36 ± 0.36* | 1.00 ± 0.44 | 2.47 ± 1.05 | 0.46 ± 0.22 | 1.95 ± 0.48 |
| Postdischarge (imp/s) | 1.28 ± 0.42 | 0.24 ± 0.24† | 0.46 ± 0.17 | 1.25 ± 0.51 | 0.10 ± 0.06 | 1.49 ± 0.39 |
| Total response duration (s) | 20.35 ± 5.97 | 6.02 ± 6.02† | 38.4 ± 9.2 | 47.84 ± 19.10 | 4.84 ± 2.47 | 22.14 ± 3.43 |
| Mean discharge rate response (imp/s) | 2.6 ± 0.5 | 0.33 ± 0.33† | 2.55 ± 0.75 | 4.44 ± 0.87 | 1.88 ± 1.26 | 3.88 ± 0.89 |
| n | 7 | 6 | ||||
| Amitriptyline | ||||||
| Ongoing activity (imp/s) | 0.02 ± 0.02 | 0 ± 0 | 0.22 ± 0.15 | 0.09 ± 0.05 | 0.09 ± 0.09 | 0.09 ± 0.07 |
| Latency (s) | 13.80 ± 2.89 | 48.3 ± 7.40† | 28.03 ± 10.25 | 17.66 ± 3.29 | 39.65 ± 7.70 | 24.17 ± 6.24 |
| Activity during the pulse (imp/s) | 1.32 ± 0.33 | 0.07 ± 0.05* | 1.25 ± 0.52 | 1.56 ± 0.36 | 0.36 ± 0.25* | 1.79 ± 0.50 |
| Postdischarge (imp/s) | 0.51 ± 0.25 | 0.08 ± 0.07 | 0.52 ± 0.27 | 1.40 ± 0.39 | 0.17 ± 0.10* | 1.30 ± 0.44 |
| Total response duration (s) | 27.28 ± 6.59 | 4.52 ± 2.15* | 27.18 ± 2.87 | 23.92 ± 6.52 | 4.24 ± 2.10* | 17.92 ± 3.64 |
| Mean discharge rate response (imp/s) | 3.44 ± 1.31 | 0.46 ± 0.26* | 3.03 ± 0.53 | 3.50 ± 0.59 | 1.89 ± 0.75 | 3.90 ± 1.01 |
| n | 6 | 7 | ||||
Data are mean ± SEM of the values obtained before and after topical application of the corresponding drug during 10 minutes; n = number of tested fibers. * P < 0.05, †P < 0.01, paired t-test or Wilcoxon signed rank test, as appropriate.