Table 1: Effects of essential oil (EO) of C. limon, morphine (MOR), and naloxone (NAL) on writhing induced by acetic acid.

TreatmentDose (mg/kg)No. of writhings*% inhibition

Vehicle14.6 ± 2.7
EO503.7 ± 0.6a75
EO1003.6 ± 0.82a76
EO1502.9 ± 0.9a,b,c81
EO plus NAL150 + 1.510.5 ± 1.7a,d27
MOR51.6 ± 0.5a91
MOR plus NAL5 + 1.511.2 ± 1.9e,f23

per group.
*Values represent mean ± SEM.
a , significantly different from control, b , significantly different from EO 50 group, c , significantly different from EO 100 group. d , significantly different from EO 150 group, e , significantly different from EO plus NAL group, f , significantly different from MOR group. One-way ANOVA followed by Dunnett’s test was applied to all data.