PMC

Effect of contralaterally administered CBD on ipsilateral pain behaviour. The improvement in hind paw withdrawal threshold seen with ipsilateral CBD was not observed when CBD (300 μg i.artic.) was administered to the contralateral knee (A). Contralateral CBD did not significantly decrease hind paw weight bearing (B) when compared with ipsilateral CBD. (*P < 0.05, **P < 0.01 1-way ANOVA with Fisher post hoc test; n = 8-9). Data are mean values ± SEM. ANOVA, analysis of variance; CBD, cannabidiol; VEH, vehicle.

Study schema. CBD, cannabidiol; cLBP, chronic low back pain.

The corneal antinociceptive and anti-inflammatory effects of CBD are mediated through 5-HT_1A receptor. (A) Pain score measured at 6 h postcauterization in WT mice preadministered with the 5-HT_1A receptor antagonist, WAY100635 (1.0 mg/kg i.p.), and treated topically with 5 μL of either vehicle (n=8) or 5% CBD (n=8). (B) The number of neutrophils per section measured at 12 h postcauterization in corneas from WT mice treated with 5 μL of either vehicle (n=6) or 5% CBD (n=6). Values represent mean±SD. For statistical analysis, unpaired t-tests were used.

Analgesic potential of 50 mg/kg CBD at Day 20 and 21 post MIA induction modulated by coadministration of TRPV1 and TRPA1 antagonists. CBD was administered i.p. two hours before assessment. The TRPV1 antagonist SB-366791 (SB; 1 mg/kg) and TRPA1 antagonist AP-18 (AP; 0.2 mg/kg) were administered i.p. 30 min before the assessment. Pain was assessed at baseline at day 20 post MIA and 2 h after i.p. administration of CBD with or without antagonists at day 21 post MIA (A–C). Two-way ANOVA revealed significant treatment effect in all tests (p < 0.0001). Individual data points are shown in box and whisker plots presenting means ± min to max. The control and MIA groups included N = 8 rats, whereas the CBD group without antagonists (CBD, SB, AP) included N = 5 rats. ● denotes samples in control group; ■ denotes samples in MIA group; ▲ denotes samples in MIA + CBD group; ▼ denotes samples in MIA + CBD + SB-366791 group; ♦ denotes samples in MIA + CBD + AP-18 group. The difference was considered significant when p < 0.05. * Denotes significant differences compared with the vehicle-treated control group of healthy animals; # denotes difference compared with the vehicle-treated MIA group; $ denotes difference compared with the CBD group.