Table 1 Summary of binding interactions (Ki values) and functional activation ([35S]GTPγS binding assay) of THC and PET diastereoisomers on human CB1R and CB2R.

Emax values represent the maximal [35S]GTPγS binding expressed as percentage of the vehicle-treated sample (100%). “Full” and “partial” in brackets stand for full and partial agonist.

Receptor binding
Ki values (nM, mean ± SD)
Receptor activation
EC50 (nM) and Emax (%) values (mean ± SD)
CannabinoidCB1RCB2RCB1R (EC50)CB1R (Emax)CB2R (EC50)CB2R (Emax)
CP55,9401.2 ± 0.50.7 ± 0.317 ± 9173 ± 6
(full)
1.9 ± 0.8194 ± 5
(full)
Δ9-trans-THC22 ± 1347 ± 1143 ± 30146 ± 3
(partial)
12 ± 7134 ± 4
(partial)
Δ9-cis-THC228 ± 4599 ± 29552 ± 123158 ± 6
(partial)
119 ± 69153 ± 5
(partial)
trans-PET127 ± 82126 ± 55171 ± 116142 ± 5
(partial)
478 ± 288116 ± 6
(partial)
cis-PET481 ± 125225 ± 61406 ± 175142 ± 5
(partial)
167 ± 136113 ± 4
(partial)