Methanolic Extract of Clinacanthus nutans Exerts Antinociceptive Activity via the Opioid/Nitric Oxide-Mediated, but cGMP-Independent, Pathways

Figure 4

Effect of MECN on formalin-induced paw licking in rats. (a) Early phase; (b) late phase. Rats were treated with vehicle (10 mL/kg, p.o.), ASA (100 mg/kg, p.o.), MECN (100, 250, and 500 mg/kg, p.o.), or morphine (5 mg/kg, p.o.) 60 min before intraplantar administration of 5% formalin (50 μL in distilled water) into the right hind paw. Naloxone (Nalox, 5 mg/kg, i.p.) was administered 15 min before MECN (500 mg/kg, p.o.) or vehicle (10 mL/kg, p.o.). Each column represents the mean ± SEM of six rats. Statistical analyses were performed using 1-way ANOVA followed by Tukey’s post hoc test. , , and compared to control group; , compared to 500 mg/kg MECN-treated group. Values in parentheses denote percentage of inhibition.

(a)

(b)