TABLE 1

Pharmacodynamic properties of Δ9-THC, CBD, and CBG at cannabinoid receptors

Binding affinities for Δ9-THC, CBD, and CBG at the two canonical cannabinoid receptors (CB1 and CB2), as well as a third receptor, GPR55 (commonly referred to as CB3). Δ9-THC acts as an agonist at all three receptors, whereas CBD acts as an antagonist; CBG acts as a weak or partial agonist at CB1 and CB2, and its function at GPR55 is currently unknown.

Δ9-THCCBDCBG
ReceptorAffinityFunctionAffinityFunctionAffinityFunction
nMnMnM
CB15.1–80.3 (Ki)a,bPartial agonist1458.5–4900 (Ki)a,bInverse agonist/antagonist440–1045 (Ki)b,c,d,eWeak agonist
CB23.1–75.3 (Ki)a,bAgonist372.4–4200 (Ki)a,bInverse agonist153.4–1225 (Ki)b,c,d,ePartial agonist
GPR558 (EC50)fAgonist445 (IC50)fAntagonistN.T.Unknown
  • N.T., not tested.

  • a Pertwee (2008).

  • b Rosenthaler et al. (2014).

  • c Cascio et al. (2010).

  • d Pollastro et al. (2011).

  • e Navarro et al. (2018).

  • f Ryberg et al. (2007).