THCP Receptor Affinity Is Not a Human Intoxication Multiplier
Strong THCP binding to a human cannabinoid receptor in vitro does not establish how many times more intoxicating it is in people. The supplied discovery study combined chemical identification, receptor testing and mouse experiments, each answering a different question.
The discovery included receptor-level evidence
Citti and colleagues identified delta-9-tetrahydrocannabiphorol, or THCP, with a seven-carbon side chain in a medicinal cannabis variety. They characterized the compound and examined its affinity for cannabinoid receptors.
The reported in-vitro affinity at human CB1 receptors was high, with a Ki of 1.2 nM. A lower Ki indicates stronger binding in that assay; it is not a direct measurement of a human intoxicating dose or duration.
The functional experiment involved mice
The investigators also observed cannabinoid-like effects in a mouse tetrad: reduced movement, analgesia, catalepsy and reduced body temperature. Those findings support biological activity in the tested animal model.
Using a human receptor preparation does not make the receptor experiment a human clinical trial. Likewise, mouse responses cannot supply a numerical multiplier for subjective intoxication, driving impairment or a safe dose in people.
Keep the proposed contribution provisional
The discovery raised the possibility that minor cannabinoids contribute to differences among cannabis varieties. It did not quantify THCP’s contribution to intoxication in consumers of a particular product.
For product or forensic claims, identify whether the evidence concerns chemical presence, receptor binding, animal response or a measured human outcome. This study supports the first three categories without establishing a human potency conversion or validating claims about present-day retail preparations.
Related: Separating cannabis exposure, impairment and crash risk.
Research cited
Citti C; Linciano P; Russo F; et al.; Scientific Reports; 2019. A novel phytocannabinoid isolated from Cannabis sativa L. with an in vivo cannabimimetic activity higher than delta-9-tetrahydrocannabinol: delta-9-Tetrahydrocannabiphorol.
