The role of the ECS in the keratinocytes of healthy dogs was recently analyzed, and the upregulation of the cannabinoid receptors (CB1R and CB2R) and cannabinoid-related receptors (GPR55, TRPV1, TRPA1; PPARα, serotonin 1A [5-HT1aR]) was evaluated in dogs with AD (45). Here, GPR55 is linked to Alzheimer disease.