RESUMEN
The objective of the present investigation was to assess the possible involvement of GABAergic mechanism in analgesic effect of aqueous extract of Origanum Vulgare (ORG) in a rat model of acute pain test. Sixty-three anaesthetized male Wistar rats (200-250 g) were cannulated into the left ventricle. Five to seven days after the recovery from surgery, ORG extract was intraventricularly injected at dose of 3 µg/rat i.c.v. Then, baclofen (10 mg/Kg, IP), CGP35348 (100 nmol/Kg, i.c.v), muscimol (1 mg/Kg IP) and bicuculline (5 mg/Kg IP) were separately injected 20 min before the injection of ORG. The experimental groups were compared with intact (control) group (n = 7). The response latency of rats to thermal stimulation was recorded using Tail-Flick test. Injection of ORG extract resulted in a significant and dose-dependent increase in the response latency. There was also a significant increase in the response latency after co-administration of ORG extract with baclofen when compared with control group. However, following co-administration of ORG extract/bicuculline, a significant decrease in the response latency was observed compared to control group. In conclusion, the results of the present study suggest that aqueous extract of Origanum vulgare L. ssp. viridis possesses antinociceptive activity in a dose-dependent manner and ORG-induced antinociception might be mediated, at least in part, by both GABA receptors.
RESUMEN
OBJECTIVE(S): The aim of study was to investigate the antinociceptive effect of intracerebroventricular (ICV) microinjection of Origanum vulgare (ORG) extract and possible involvement of opioid receptors. MATERIALS AND METHODS: Cannula was inserted into left ventricle of male rats. Five days after surgery Tail Flick Latency (TFL) was measured after ICV microinjection of, ORG (1, 3 and 6 µg / rat). Effective dose of ORG was injected ICV in concomitant with morphine (2 mg/kg, IP), naloxone (2 mg / kg, IP) and saline (0.5 µl/rat) and TFL was recorded. RESULTS: The co- administration of ORG extract with morphine showed a significant increase in TFL and naloxone, pretreatment significantly inhibited the antinociceptive activity of ORG and morphine. CONCLUSION: The aqueous extract of ORG possesses antinociceptive activities in the tail-flick test in a dose dependent manner. ORG - induced antinociception may have been mediated by opioid systems.