Table 2 Selectivity of Opioid receptors to the Endogenous Opioid Peptides and Exogenous Opioid Drugs
From: Molecular and cellular mechanisms of the age-dependency of opioid analgesia and tolerance
Opioid receptor | Endogenous opioid peptides | Opioid drugs |
|---|---|---|
Μ-receptor | β-endorphin | morphine |
| Â | enkephalin | fentanyl |
| Â | Â | sufentanil |
| Â | Â | D-Ala2,MePhe4,Gly-ol5 |
| Â | Â | (DAMGO) |
δ-receptor | Met-enkephalin | deltorphin |
| Â | Leu-enkephalin | [D-Pen2,D-Pen5]enkephalin |
| Â | Â | (DPDPE) |
κ-receptor | dynorphin A | ethylketocyclazocine (EKC) |
| Â | dynorphin B | buprenorphine |
| Â | Â | pentazocine |
| Â | Â | U 50,488 |
ORL1-receptor | nociceptin | None |