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

Figure 5

The involvement of L-arg/NO/cGMP pathway in the modulation of MECN antinociception as assessed using the abdominal constriction test. (a) Effects of pretreating animals with L-arg, L-NAME, or their combination on the antinociceptive activity of MECN. (b) Effects of L-arg, ODQ, or their combination on the antinociceptive activity of MECN. Animals were treated with MECN (500 mg/kg, p.o.) or vehicle (10 mL/kg, p.o.) 60 min before acetic acid (0.6%, 10 mL/kg, i.p.) treatment. L-arg (20 mg/kg, i.p.), L-NAME (20 mg/kg, i.p.), ODQ (2 mg/kg, i.p.), or combinations thereof (L-arg + L-NAME or L-arg + ODQ) were administered 5 min before MECN (500 mg/kg, p.o.) or vehicle (10 mL/kg, p.o.). Each column represents the mean ± SEM of six mice. Statistical analyses were performed using 1-way ANOVA followed by Tukey’s post hoc test. compared to control group; , compared to 500 mg/kg MECN, L-NAME, L-arg, L-arg + L-NAME, or L-arg + ODQ group.

(a)

(b)