Endogenous and selective opioid peptides used in this study
| Peptide | Sequence |
|---|---|
| Enkephalins | |
| Leu-enk | Tyr-Gly-Gly-Phe-Leu |
| Met-enk | Tyr-Gly-Gly-Phe-Met |
| Met-enk-RF | Tyr-Gly-Gly-Phe-Met-Arg-Phe |
| Dynorphins | |
| Dynorphin A (DynA) | Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys-Trp-Asp-Asn-Gln |
| Dynorphin B | Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Gln-Phe-Lys-Val-Val-Thr |
| DynA 1–13 | Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys |
| DynA 1–8 | Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile |
| DynA 1–6 | Tyr-Gly-Gly-Phe-Leu-Arg |
| α-Neo | Tyr-Gly-Gly-Phe-Leu-Arg-Lys-Tyr-Pro-Lys |
| Endorphins | |
| β-Endorphin | Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Val-Thr-Leu-Phe-Lys-Asn-Ile-Ile-Lys-Asn-Ala-Tyr-Lys-Lys-Gly-Glu |
| Endomorphins | |
| Endo-1 | Tyr-Pro-Trp-Phe |
| Endo-2 | Tyr-Pro-Phe-Phe |