Table 1. Acute hypernociception: Effect of pretreatment with l-NMMA, ODQ, and KT5823 on the antinociceptive effect of morphine, dipyrone, SNAP, 8-Br-cGMP, or diazoxide.
| Pretreatment
|
||||
|---|---|---|---|---|
| Treatment | Saline | l-NMMA | ODQ | KT5823 |
| PGE2+ Control | 16.5 ± 1.0 | 16.7 (ns) ± 0.8 | 16.7 (ns) ± 0.5 | 15.7 (ns) ± 1.0 |
| PGE2+ Morphine | 5.5* ± 0.8 | 13.1† ± 1.1 | 14.5† ± 0.6 | 14.3† ± 0.8 |
| PGE2+ Dipyrone | 4.3* ± 0.8 | 15.0† ± 0.5 | 13.8† ± 1.0 | 13.5† ± 0.9 |
| PGE2+ SNAP | 6.1* ± 1.0 | 7.1 (ns) ± 0.5 | 12.0† ± 0.3 | 13.3† ± 0.2 |
| PGE2+ 8-Br-cGMP | 5.8* ± 0.6 | 7.2 (ns) ± 1.3 | 6.8 (ns) ± 1.3 | 11.7† ± 0.7 |
| PGE2+ Diazoxide | 9.8* ± 0.7 | 11.3 (ns) ± 0.2 | 11.4 (ns) ± 0.7 | 10.0 (ns) ± 0.8 |
Morphine (6 μg), dipyrone (160 μg), SNAP (200 μg), 8-Br-cGMP (300 μg), and diazoxide (600 μg) were injected 2 h after i.pi. injection of PGE2 (100 ng). The i.pl. pretreatments with l-NMMA (50 μg) or ODQ (8 μg) were given 30 min before treatment, with the exception of KT5823 (1.5 μg), which was given 10 min before treatment. Hypernociception was measured 3 h after PGE2 injection. *, P < 0.05 compared with PGE2-control injected rats pretreated with saline. †, P < 0.05 compared with morphine-dipyrone-, SNAP-, 8-Br-cGMP-, or diazoxide-injected paws pretreated with saline, respectively. ns, nonsignificant compared with the respective controls. The intensity of mechanical hypernociception was expressed in seconds. The data are the means (±SEM) of five animals per group.