Mu opioid receptor antagonist 3 (compound 26) is a potent and selective mu opioid receptor (MOR) antagonist that penetrates the blood-brain barrier (Ki: 0.24 nM, EC50: 0.54 nM). Mu opioid receptor antagonist 2 can be used to study opioid use disorder (OUD).

μ opioid receptor agonist 2 （Compound H-3）is a MOR receptor agonist. μ opioid receptor agonist 2 can be used for the research of pain and pain related diseases.

σ 1 Receptor/ μ Opioid receiver modulator 1 (Compound 44) is an effective σ 1 receptor antagonist (Ki=1.86 nM) and μ Opioid receptor agonists (Ki=2.1 nM). Opioid receptor modulator 1 shows potent analgesic activity, and can be used for the research of neuropathic pain.

Compound 24, also known as Mu opioid receptor antagonist 7, is a potent, centrally-acting µ-opioid receptor (µOR) antagonist with an inhibitory concentration (IC50) of 29 ± 3.0 nM. It is valuable for pain and opioid use disorder research [1].

Mu opioid receptor antagonist 4 (compound 31) is a potent and selective mu opioid receptor (MOR) antagonist that permeates the blood-brain barrier (Ki: 0.38 nM, EC50: 0.38 nM). Mu opioid receptor antagonist 2 can be used to study opioid use disorder (OUD).

Mu opioid receptor antagonist 2 (compound 25) is a potent and selective mu opioid receptor (MOR) antagonist that permeates the blood-brain barrier (Ki: 0.37 nM, EC50: 0.44 nM). Mu opioid receptor antagonist 2 can be used to study opioid use disorder (OUD).

Compound 20, identified as μ opioid receptor agonist 3, is a potent µOR agonist that exhibits an EC50 value of 0.87 nM. It holds promise for research into pain management and neuropsychiatric disorders [1].

μ opioid receptor agonist 1 (Compound H-1a) is an optically pure oxyheterocyclic substituted pyrroloxypyrazole derivative and an MOR receptor agonist that can be used in the study of pain and pain-related disorders.

Mu opioid receptor antagonist 5 (compound NAP) is a selective mu opioid receptor (MOR) antagonist that crosses the blood-brain barrier (EC50: 1.14 nM, Ki: 0.37 nM). Mu opioid receptor antagonist 5 can be used to study opioid use disorder (OUD).

Potent, selective agonist of Mu-opioid receptor. Antinociceptive. Stimulates calcium-activated adenylyl cyclases related cAMP production. Expresses chemokines and chemokine receptors through TGF-beta1. Increases food intake of rats.

BTRX-335140 (CYM-53093) is a potent and selective, orally active κ opioid receptor (KOR) antagonist, has antagonist activity for κOR, μOR and δOR with IC50 values of 0.8 nM, 110 nM, and 6500 nM, respectively. BTRX-335140 can distribute well into the CNS. ADMET (absorption, distribution, metabolism, excretion, and toxicity) . BTRX-335140 endows with favorable in vitro ADMET and in vivo pharmacokinetic profiles and medication-like duration of action in rats.

JTC-801 is a selective opioid receptor-like1 (ORL1) receptor antagonist with IC50 of 94 nM, weakly inhibits receptors δ, κ, and μ.

CP-866087 is a novel, potent and selective mu-opioid receptor antagonist for the study of female sexual dysfunction.

β-Endorphin (1-27) (human) acetate, existing in the hypophysis cerebri and hypothalamus, exhibits antinociception activity. β-Endorphin (1-27) (human) acetate is an agonist of opioid receptor, showing preferred affinity for μ-opioid receptor and δ-opioid

Adrenorphin 3TFA(88377-68-8(free base)) (Metorphamide) is an agonist of μ-opioid receptor(Ki :12 nM).

Acetyl tetrapeptide-15 Acetate (Skinasensyl Acetate), a synthetic peptide used in cosmetic products for sensitive skin, is an endomorphin-2 derivative that extends the range of neuronal excitability thresholds in the μ-opioid receptor via an endorphin-like pathway, and can be used to study inflammatory and neuropathic pain produced by skin hyperreactivity. Inflammatory and neuropathic pain produced by skin hyperresponsiveness.

1,1'-(Octane-1,8-diyl)diguanidine dihydrochloride is a synthetic opioid peptide derived from the natural opioid peptide enkephalin. It is a potent agonist of the mu-opioid receptor (MOR) with a Ki of 0.14 nM, making it one of the most potent MOR agonists known to date.

Samidorphan HCl is an orally active and highly potent modulator of the opioid system that binds to μ‐opioid, κ‐opioid, and delta-opioid receptors. Samidorphan HCl is a novel μ-opioid receptor antagonist, a partial agonist for k-opioid and delta-opioid receptors. Samidorphan HCl can be used to prevent and treat schizophrenia.

CTAP(TFA) (103429-32-9 free base) is a potent, highly selective, and brain-penetrant antagonist of the μ-opioid receptor with IC50 of 3.5 nM. It displays over 1200-fold selectivity over δ opioid (IC50=4500 nM) and somatostatin receptors. CTAP(TFA） (103429-32-9 free base) can be used for the study of L-DOPA-induced dyskinesia (LID)

Endomorphins-2 (EM-2) could decrease both the frequency and amplitude of the sEPSC of the motoneurons in lamina IX, which was reversed by the MOR antagonist CTOP. EM-2-IR fibers originated from primary afferent fibers form symmetric synaptic connections with motoneurons innervating skeletal muscles of the lower limbs in lamina IX of the spinal ventral horn and EM-2 might exert inhibitory effects on the activities of these motoneurons through both presynaptic and postsynaptic mechanisms.

[(pF)Phe4]Nociceptin(1-13)NH2 acetate is a selective agonist of NOP receptor with a pKi of 10.68 and a pEC50 of 9.31. [(pF)Phe4]Nociceptin(1-13)NH2 acetate displays high selectivity over δ, κ, and μ opioid receptors (>3000 fold).

[Leu5]-Enkephalin acetate(58822-25-6 free base) is an endogenous neuropeptide involved in nociception and an agonist of δ-opioid and μ-opioid receptors (Kis = 4.0 and 3.4 nM, respectively)

JNJ-20788560 is a delta opioid receptor (DOR) agonist with analgesic activity. It is more selective for DOR than for mu opioid receptors (MOR).

CTOP acetate is a somatostatin analogue and a μ-opioid receptor antagonist.

Orphanin FQ(1-11) acetate(178249-41-7 free base) is a peptide fragment containing amino acids 1-11 of Nociceptin. Orphanin FQ(1-11) acetate(178249-41-7 free base) is a potent agonist of the ORL1/KOR-3 receptor (Ki = 55 nM) and displays no affinity for opioid receptors, including μ, δ, κ1 and κ3 receptors (Ki >1000 nM). Orphanin FQ(1-11) acetate(178249-41-7 free base) displays analgesic properties in CD-1 mice.

UFP-101 acetate is a selective and competitive antagonist of the NOP receptor (pKi = 10.24) with >3000-fold selectivity over δ, μ, and κ opioid receptors.

AT-121 is a dual μ-opioid and neuropeptide receptor partial agonist (Kis 16.49 and 3.67 nM, respectively). It stimulates [35S]GTPγS binding to cell membranes expressing either μ-opioid receptors or neuropeptide receptors (EC50s of 19.6 and 34.7 nM, respectively.) AT-121 (0.003-0.03 mg/kg) reduced capsaicin-induced thermal anisocoria in a dose-dependent manner, but did not increase scratching activity in rhesus monkeys. In rhesus monkey drug self-administration tests, AT-121 at doses of 0.3 to 10 μg/kg per injection lacked reinforcing effects (a potential marker of abuse) and did not reduce the reinforcing effects of food pellets.AT-121 (0.01 or 0.03 mg/kg) did not induce hyperalgesia, a marker of tolerance, in rhesus monkeys.AT-121 is a safe non-addictive pain reliever with anti-injury and analgesic effects.

SNC 80 (NIH 10815) is a potent, highly selective and non-peptide δ-opioid receptor agonist, Ki = 1.78 nM, IC50 = 2.73 nM. SNC80 also selectively activates μ-δ heteromer in HEK293 cells with an EC50 of 52.8 nM. SNC80 shows antinociceptive, antihyperalgesic and antidepressant‐like effects. SNC80 has the potential for multiple headache disorders treatment.

Methylnaltrexone bromide (MOA-728) is one of the newer agents of peripherally-acting μ-opioid antagonists. Methylnaltrexone bromide acts to reverse some of the side effects of opioid drugs such as constipation without affecting analgesia or precipitating withdrawals.

BW-180C (DADLE) is a prototypical δ-opioid receptor agonist that also displays activity at the μ-opioid receptor. Displays antinociceptive activity in vivo.

DAMGO (DAGO) is an opioid receptor agonist with the ability to affect the locomotive activity in rodents. Possible analgesic agent due to μ-opiod receptor interaction.

SR17018 is an mu-opioid-receptor (MOR) agonist, binding with GTPγS, with an EC50 of 97 nM.

Potent and selective μ opioid receptor antagonist (Ki values are 0.96 and >10,000 nM for μ and δ receptors respectively). Causes behavioral effects on central administration in vivo. Also increases K+ currents in rat locus ceruleus neurons in vitro via a

β-Endorphin (β-EP) is an endogenous opioid neuropeptide with diverse biological activities. It is produced via piomelanocortin cleavage in the pituitary gland, hypothalamus, and in lymphocytes, then migrates to its sites of action which include plasma, gut, skin, placenta, cerebrospinal fluid, and cardiac tissues. β-EP induces concentration-dependent decreases in electrically stimulated contraction of the mouse vas deferens that can be reversed by the μ-opioid antagonist CTP and δ-opioid antagonist ICI 174,864. In vivo, β-EP (5 μg, i.c.v.) slows gastrointestinal transit in mice. β-EP (0.5 or 5 μg, i.c.v.) stimulates food intake in rats for 4 to 6 hours, however, this effect is not prolonged with continuous infusion. It antagonizes the appetite-suppressive effects of α-melanocyte-stimulating hormone (α-MSH) for the first three days post administration. β-EP also reduces paralytic demyelination induced by the murine coronavirus MHV-JHM in immunocompetent, but not irradiated or immune-incompetent, mice and rats.

Valorphin (Valorphin TFAsalt) has opioid analgesic activity, binds to rat mu-opioid receptor, with an IC50 of 14 nM.

Potent and selective μ opioid receptor antagonist (IC50 = 3.5 nM). Displays > 1200-fold selectivity over δ opioid and somatostatin receptors. Brain penetrant and active in vivo.

Gluten exorphin C is an opioid peptide derived from wheat gluten. Its IC50 values are 40 μM and 13.5 μM for μ opioid and δ opioid activities in the GPI and MVD assays, respectively.Gluten Exorphin C, isolated from the pepsin-trypsin-chymotrypsin digest of wheat gluten, was considered as a δ-opioid receptor-selective ligand.

Potent, selective partial agonist peptide for the NOP receptor (Ki = 0.71 nM). Selective over μ, δ and κ opioid receptors (IC50 > 4000 nM). Increases food intake in vivo.

Dermorphin is agonist of μ-opioid receptor (MOR) agonist.

Adrenorphin (Metorphamide)(3TFA) is an agonist of μ-opioid receptor(Ki :12 nM).

Axelopran(TD-1211) is potentially useful for the treatment of opioid-induced constipation, it is a potent, selective, and peripherally-restricted μ-, κ-, and δ-opioid receptor antagonist.

Highly potent and selective NOP receptor agonist (EC50 = 1 nM). Displays > 875-fold selectivity over opioid receptors (IC50 values are 0.32, 280, > 10000 and 1500 for NOP, μ, δ and κ receptors respectively). Longer lasting and 30-fold more potent than noc

Orphanin FQ(1-11) is a peptide fragment containing amino acids 1-11 of Nociceptin. Orphanin FQ(1-11) is a potent agonist of the ORL1/KOR-3 receptor (Ki = 55 nM) and displays no affinity for opioid receptors, including μ, δ, κ1 and κ3 receptors (Ki >1000 nM). Orphanin FQ(1-11) displays analgesic properties in CD-1 mice.

Potent, selective and competitive silent antagonist for the NOP opioid receptor. Binds to NOP with high affinity (pKi = 10.24) and displays > 3000-fold selectivity over δ, μ and κ opioid receptors. Antinociceptive and opposes the action of nociceptin in v

UFP-101 TFA is a potent, selective, and competitive N/OFQ peptide (NOP) receptor antagonist, boasting a pK i value of 10.24 and demonstrating over 3000-fold selectivity against δ, μ, and κ opioid receptors. It exhibits antidepressant-like effects [1] [2].

GSK1521498 free base (hydrochloride) is a selective antagonist of the μ-opioid receptor (MOR). It is being used for the treatment of disorders of compulsive consumption of food, alcohol, and drugs.

β-Endorphin (1-27) (human) is an opioid antagonist that selectively binds to μ-, δ-, and κ-opioid receptors, with dissociation constants (Kis) of 5.31, 6.17, and 39.82 nM, respectively. It inhibits analgesia induced by both β-Endorphin and etorphine [1] [2].

Metkephamid acetate is a synthetic opioid pentapeptide and derivative of [Met]enkephalin. It shows as a potent agonist of the δ- and μ-opioid receptors with roughly equipotent affinity, and also has similarly high affinity as well as subtype-selectivity f

Tianeptine metabolite MC5, an active derivative of the atypical antidepressant tianeptine produced through β-oxidation, exhibits selective G protein activation in bioluminescence resonance energy transfer (BRET) assays. Utilizing HEK293T cells expressing the human μ-opioid receptor (MOR) over the human δ-opioid receptor (DOR; EC50s = 0.454 and >100 µM, respectively), it demonstrates specificity. Moreover, this metabolite reduces immobility in wild-type mice during the forced swim test at a dose of 30 mg/kg, an effect not observed in MOR knockout mice, suggesting its antidepressant-like activity is MOR-dependent.

DS34942424 is an orally potent analgesic which did not exhibit mu opioid receptor agonist activity.