α2 receptors are classically known as adrenalin receptors. However, α2 receptors also bind CBG at very high affinity and are therefore also cannabinoid receptors. The interaction between CBG and α2 receptors may be relevant in the treatment of pain and Depression, but more research is required.

Diseases: 
Chemical Name: 
Alpha-2 adrenergic receptor
IUPHAR entry: 
Wikipedia entry: 
Phytocannabinoids: 
Literature Discussion: 

CBG can activate α2 receptors and block CB1 and 5-HT1A receptors (Cascio et al., 2010), suggesting CBG does have therapeutic potential in the treatment of Depression.

References:

Cascio, M.G., Gauson, L.A., Stevenson, L.A., Ross, R.A., and Pertwee, R.G. (2010). Evidence that the plant cannabinoid cannabigerol is a highly potent alpha2-adrenoceptor agonist and moderately potent 5HT1A receptor antagonist. Br. J. Pharmacol. 159, 129–141.