OPRM1 and inflammation: In particular, the acid cinnamic derivative PR-38 (11, Figure 3) [40], with Ki values at MOR and KOR of 52 and 9.6 nM coupled to a potent dual MOR/KOR agonist profile, resulted a potential anti-inflammatory and analgesic agent for gastrointestinal inflammation [41] in a mouse model of hypermotility, diarrhea, and abdominal pain.