. 2019 Nov 19;24(22):4190. doi: 10.3390/molecules24224190

Table 1.

Binding profile of selected ligands at the human opioid receptors [51] ^.

Ligand	Ki [nM]				Action	Compound Class	Ref.
Ligand	μ-OR	δ-OR	κ-OR	NOP	Action	Compound Class	Ref.
Met⁵-enkephalin	261	9.9	-	-	agonist δOR	EOP	Stefanucci [52]
Leu⁵-enkephalin	513	10.7	-	-	agonist δOR	EOP	Stefanucci [52]
β-Endorphin	2.1	2.4	96	-	agonist μOR, κOR	EOP	Corbett [53]
Dinorphin A	1.6	1.25	0.05	386	agonist κOR	EOP	Zhang [54]
Nociceptin	437	2846	147	0.08	agonist	EOP	Cami-Cobeci [50]
Morphine	2.06	>10,000	134	>10,000	agonist μOR	EM	Valenzano [55]
Oxycodone	16	7680	43,000	-	agonist μOR	EM	Miyazaki [56]
Naltrexone	0.62	12.3	1.88	-	antagonist	EM	Zheng [57]
Carfentanil	0.07	-	-	-	agonist μOR	4-AP	Henriksen [58]
Carfentanil^a	0.051	4.7	13	-	agonist μOR	4-AP	Frost [59]
Carfentanil^b	0.024	3.28	43.1	-	agonist μOR	4-AP	Cometta [60]
Cyclofoxy^a	2.62	89	9.3	-	antagonist μOR, κOR	EM	Rothman [38]
DPN	0.07	0.23	0.02	-	antagonist	orvinol	Raynor [61]
BPN	1.5	6.1	2.5	77.4	partial μOR agonist, κOR antagonist	orvinol	Cami-Cobeci [50]
PEO	0.18	5.1	0.12	-	full agonist	orvinol	Marton [62]
FE-DPN	0.24	8.00	0.20	-	antagonist	orvinol	Schoultz [63]
FE-BPN	0.24	2.10	0.12	-	mixed agonist/antagonist	orvinol	Schoultz [63]
FE-PEO	0.10	0.49	0.08	-	full agonist	orvinol	Schoultz [63]
NTI^b	3.8	0.03	332	-	antagonist δOR	EM	Portoghese [64]
MeNTI^b	14	0.02	65	-	antagonist δOR	EM	Portoghese [64]
GR103545	16.2	536	0.02	-	agonist κOR	ArAP	Schoultz [65]
LY2459989^a	7.68	91.3	0.18	-	antagonist κOR	APPB	Zheng [66]
LY2795050	25.8	153	0.72	-	antagonist κOR	APPB	Zheng [57]
FEKAP	7.4	139	0.43	-	agonist κOR	ArAP	Li [67]
EKAP	8.6	386	0.28	-	agonist	ArAP	Li [68]
MeJDTic	8.88	118	1.01	-	antagonist κOR	JDTic	Poisnel [69]
Salvinorin A	>1000	5790	1.9	-	agonist κOR	NND	Harding [70]
NOP-1A	-	-	-	0.15	antagonist NOP	FDPTP	Pike [71]
MK-0911	94	-	-	0.6	antagonist NOP	SPB	Hostetler [72]

EOP: Endogenous opioid peptide, EM: 4,5-Eopxy-morphinan, 4-AP: 4-Anilidopiperidine, orvinol: 6,14-ethenomorphinan, Bentley-compound, ArAP: Arylacetamidopiperazine, APPB: Aryl- phenylpyrrolidinylmethyl-phenoxy-benzamide, JDTic: trans-3,4-dimethyl-4-(3-hydroxyphenyl)- piperidine, NND: “non nitrogenous” diterpene, FDPTP: 2′-fluoro-4′,5′-dihydrospiro[piperidine- 4,7′-thieno [2,3-c]pyran]- derivative, SPB: [[spiro[2.5]octan-8-yl]-methyl]piperidin-4-yl] benzimidazol-2-one, ^a: in the rat brain ^b: in guinea pig brain membranes.