Figure 1.
Structures of JWH-018 and six JWH-018 hydroxylated products.
A. JWH-018 [(1-pentyl-1H-indol-3-yl)-1-naphthalenyl-methanone] B. M1 [(4-hydroxy-1-pentyl-1H-indol-3-yl)(naphthalen-1-yl)methanone] C. M2 [(5-hydroxy-1-pentyl-1H-indol-3-yl)(naphthalen-1-yl)methanone] D. M3 [(6-hydroxy-1-pentyl-1H-indol-3-yl)(naphthalen-1-yl)methanone] E. M4 [(7-hydroxy-1-pentyl-1H-indol-3-yl)naphthalen-1-yl)methanone] F. M5 [(1-(5-hydroxypentyl)-1H-indol-3-yl)(naphthalen-1-yl)methanone] G. M6 [5-(3-(1-naphthoyl)-1H-indol-1-yl)pentanoic acid].
Figure 2.
JWH-018 and M1–M5 bind CB1R with equal or greater affinity than Δ9-THC.
JWH-018 and M1, M2, M3, M4, M5, but not M6, completely displaced the radiolabeled cannabinoid [3H]CP-55,940 from CB1Rs (data not shown). Affinities for CB1Rs of JWH-018 and M1–M5 were equivalent to or up to 10-fold greater than that of Δ9-THC (*P<0.05, **P<0.01, ***P<0.001 relative to Δ9-THC, one way ANOVA with Dunnett's Multiple Comparison Test, n = 3–4).
Figure 3.
JWH-018 and M1–M5 activate CB1R.
A. Ten µM concentrations of JWH-018, M1, M2, M3, and M5 activated brain GPCRs greater than 10 µM Δ9-THC. Activation by JWH-018, M2, M3 and M5 did not differ from the full CB1R agonist CP-55,940. Values designated with different letters above the error bars are significantly different (P<0.05, one way ANOVA with Tukey's Multiple Comparison post-hoc Test, n = 3–10). B. JWH-018 and M1 stimulated G-proteins more potently and efficaciously than Δ9-THC, n = 3–4. C. GPCR activation by an estimated ED90 concentration (100 nM) of metabolites was blocked by co-incubation with 1 µM of the selective neutral CB1R antagonist O-2050 (**P<0.01, ***P<0.001 vs drug alone, Student's t-test, n = 3–7).
Figure 4.
JWH-018 and M1 decreased mouse locomotor activity in a CB1R-dependent manner, similar to Δ9-THC.
A. Intraperitoneal (i.p.) administration of 3 mg/kg JWH-018, 10 mg/kg JWH-018 M1, and 30 mg/kg Δ9-THC decreased locomotor activity relative to vehicle controls over a 10 h time course, beginning 60 min after injection. B. Area under the curve data generated from the 10 h time-course shows 3 mg/kg JWH-018, 10 mg/kg JWH-018 M1, and 30 mg/kg Δ9-THC significantly decrease locomotor activity relative to vehicle controls (*P<0.05 vs. vehicle controls, Kruskal-Wallis one-way ANOVA with Tukey HSD test, n = 5). Co-administration of each cannabinoid with the CB1R-preferring antagonist/inverse agonist AM251 (10 mg/kg) restored locomotor activity to vehicle control levels.
Figure 5.
JWH-018 and M1 decreased mouse core body temperature in a CB1R-dependent manner similar to Δ9-THC.
A. Mice administered 3 mg/kg JWH-018 and 10 mg/kg M1 (i.p.) exhibited greater depressions in core body temperature than 30 mg/kg Δ9-THC, but also recovered more quickly over a 10 h time course, resulting in B. equivalent area under the curve values, which were significantly lower than vehicle controls (*P<0.005 vs. vehicle controls, one-way ANOVA with Tukey HSD test, n = 5). Core body temperature was restored to vehicle control levels by coadministration of cannabinoids with the CB1R-preferring antagonist/inverse agonist AM251 (10 mg/kg).