Subscribe to RSS
DOI: 10.1055/s-0029-1234437
Antinociceptive activity of methanolic extract from Rhamnidium elaeocarpum barks
We evaluated the antinociceptive action of a methanolic extract from R. elaeocarpum (MeOH) and its mechanisms of action in rodent experimental models. The antinociceptive effect was evaluated by formalin method where male Swiss mice (n=5–8) received by oral route saline, piroxicam (30mg/kg) or ME (250mg/kg). After 1 hour all animals received 20µL of formalin solution 2.5% in PBS at their hinder right paw. After injection of formalin, mice were observed during 5min (neurogenic phase) and between 15–30min after infection (inflammatory phase). The time spent of licking the injected paw was recorded with a chronometer and considered as indicative of nociception index. The evaluation of involvement of nitric oxide or serotonin in the antinociceptive mechanism of ME, mice were pre-treated with L-argenine (500mg/kg, i.p, 30min before ME administration) or PCPA-p-chlorophenylalanine (100mg/kg i.p, once a day for 4 consecutive days), respectively. The statistical significance of differences between groups was detected by ANOVA followed by Dunnett test (p<0.05). The group of animals that received MeOH showed significative reductions in time of reaction during the inflammatory phase comparing to animals treated with vehicle. The antinociceptive action of extract did not reverse by L-argenine (NO precursor). But MeOH antinociceptive property was significantly reversed by PCPA (an inhibitor of serotonin synthesis).Thus, methanolic extract from Rhamnidium elaeocarpum exert antinociceptive action by serotonergic system.
Acknowledgements: Biota/FAPESP, CNPq, FAPESP proc. No 07/57377–8
Reference: [1] Hunskaar, S., Hole, K. (1987) Pain 30:103–104.