Opioid Receptor Modulator

Cyclazocine is a μ, δ, and κ opioid receptor modulator with K_i values of 0.32, 1.1, and 0.18 nM, respectively. Cyclazocine exhibits "mixed" pharmacological activities, acting as a μ-partial antagonist, κ-agonist, and low-affinity δ ligand. Cyclazocine shows antinociceptive activity in mice. Cyclazocine can be used in studies on psychoactive substance addiction.

Nalmefene is a BBB-penetrable opioid receptor modulator. Nalmefene is an antagonist of MOR and DOR, and a partial agonist of KOR. Nalmefene has anti-inflammatory and neuroprotective activities. Nalmefene can be used in the research of reducing alcohol-dependent disorders.

Samidorphan (ALKS-33) is an orally active opioid system modulator that has a high affinity for binding with μ‐opioid, κ‐opioid, and δ‐opioid receptors. Samidorphan acts as an antagonist at μ‐opioid receptors and acts as a partial agonist at k-opioid and δ‐opioid receptors. Samidorphan primarily acts as an opioid receptor antagonist in vivo. Samidorphan can improve the behavior of depressed animals.

Noribogaine hydrochloride is an orally active, blood-brain barrier permeable SERT inhibitor (IC₅₀=50-300 nM) and hERG channel blocker. Noribogaine hydrochloride enhances serotonergic transmission, activates the κ-opioid receptor (OPRK) G protein signaling pathway and inhibits β-arrestin recruitment. Meanwhile, Noribogaine hydrochloride blocks the μ-opioid receptor (OPRM) signaling pathway as well as ion channels associated with cardiac repolarization. Noribogaine hydrochloride induces neuritogenesis, upregulates GDNF mRNA expression, and modulates opioid tolerance. Noribogaine hydrochloride reduces alcohol-seeking behavior in experimental animals, and is widely used in studies related to depression, addiction, alcoholism, and cardiotoxicity.

Mitragynine pseudoindoxyl is a potent orally active agonist of the μ-opioid receptor (MOR-1, K_i=0.8 nM) and an antagonist of the δ-opioid receptor (DOR-1, K_i=3.0 nM). Mitragynine pseudoindoxyl has moderate affinity for the κ-opioid receptor (KOR-1, K_i=24 nM) and does not recruit β-arrestin-2, acting through G protein-mediated signaling pathways without β-arrestin-2-related activation. Mitragynine pseudoindoxyl produces potent analgesic activity through a mixed μ-agonist/δ-antagonist mechanism, with low side effects such as physical dependence, respiratory depression, and constipation, and no rewarding or aversive behaviors. Mitragynine pseudoindoxyl reduces hyperactivity, inhibits GI transit, and enhances characteristics, making it a potential analgesic.

BMS-986121 is a positive allosteric modulator (PAM) of the μ opioid receptor extracted from patent WO2014107344. BMS-986121 is built on a chemical scaffold representing a new chemotype for μ receptor PAMs.

β-Endorphin (rat) is an endogenous opioid neuropeptide and peptide hormone. β-Endorphin (rat) has analgesic activity and also contributes to food intake in satiated rats. β-Endorphin (rat) can be used in the research of neurological diseases such as analgesia and drug addiction.

Naloxone benzoylhydrazone (NalBzoH) is a mixed agonist/antagonist. Naloxone benzoylhydrazone is a prototypic κ3-opioid receptor agonist, and a partial agonist at the cloned μ and δ opioid receptors, and an antagonist at opioid-like NOP receptors. Naloxone benzoylhydrazone has potently analgesia effect.

DOR agonist 3 (Compound 10) is a δ-opioid receptor (DOR)-selective positive allosteric modulator. DOR agonist 3 enhances G protein signaling while reducing β-arrestin2 recruitment. DOR agonist 3 is promising for research of chronic pain and depression.

DS34942424 is an orally potent analgesic without mu opioid receptor agonist activity.

Ignavine is a conformational modulator of μ-opioid receptors (IC₅₀ = 2.0 μM). Ignavine exhibits a concentration dependent bidirectional regulatory effect in vitro. Ignavine has analgesic activity. Ignavine can be used for research on pain related conditions.

KOR agonist 5 (Compound 10a) is a KOR/MOR modulator with agonistic activity towards KOR and antagonistic activity towards MOR. KOR agonist 5 can effectively block morphine-induced antinociception and inhibition of intestinal motility. KOR agonist 5 can be used in the research of Substance Use Disorder (SUD).

6-Fluoro-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole is a ORL-1 receptor modulator. 6-Fluoro-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole regulates downstream pathways associated with nociception, cognition and physiological processes. 6-Fluoro-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole is used in the research of central nervous system diseases and pain-related disorders including anxiety, depression, Alzheimer's disease and attention deficit disorder.

BPRMU191 is a μ-opioid receptor (MOR) modulator that converts small-molecule morphinan antagonists into G protein-biased MOR agonists, thereby inducing MOR-dependent activation and analgesic effects. Co-administration of BPRMU191 with morphinan antagonists provides analgesia while reducing side effects such as gastrointestinal dysfunction, antinociceptive tolerance, and dependency-related adverse effects. BPRMU191, in combination with morphinan antagonists, offers a potential strategy for studying severe pain management and G protein-coupled receptor modulation.

HINT1-IN-1 (Compound 8) is the inhibitor for histidine triad nucleotide-binding protein 1 (HINT1) with a K_i of 1.14 μM. HINT1-IN-1 affects the cross-regulation between μ-opioid receptor (MOR) and NMDA receptor (NMDAR). HINT1-IN-1 enhances the analgesic effect of morphine without causing opioid tolerance and has independent analgesic effects in mouse model.

DBPR116 is a prodrug of BPRMU191 (HY-159923) with blood-brain barrier penetration capability. DBPR116 significantly improves the delivery of centrally targeted drugs. In combination with the antagonist Naltrexone (HY-76711), DBPR116 demonstrated superior safety and analgesic efficacy compared to morphine in various in vivo pharmacological studies, including thermal pain models, cancer pain models, constipation, sedation, psychological dependence, heart rate, and respiratory frequency. As a prodrug strategy for peripheral administration, DBPR116 effectively alleviates pain while reducing adverse effects, showing potential as a safer opioid analgesic.

MOR modulator-1 (compound 6) is a potent and selective μ opioid receptor (MOR) modulator. MOR modulator-1 exhibits improved opioid receptor selectivity, enhanced in vivo antagonistic effect, and overall fewer withdrawal symptoms compared to NAT (6α-configuration). MOR modulator-1 links with carboxamido linker μ, δ, γ with K_is of 0.25, 41.1, 1.30 nM, respectively_[1]

MPAM-15 is a blood-brain barrier-penetrant pan-orthosteric allosteric modulator (PAM) of opioid receptors, with ≥16-fold selectivity for μOR over δOR and κOR. MPAM-15 acts as an anti-nociceptive potentiator and analgesic, and its activity is observed in mouse models via both intracerebroventricular and intraperitoneal administration. MPAM-15 is applicable for pain-related research.

Tyr-W-MIF-1 is an opioid tetrapeptide with opiate and antiopiate activity. Tyr-W-MIF-1 can induce analgesia.

α-Endorphin (human) is a neuropeptide, that acts on the central nervous system (CNS) and peripheral nervous system (PNS). α-Endorphin (human) binds μ-opioid receptor, and exhibits analgesic efficacy. α-Endorphin (human) regulates sexual behaviors and pleasure felling.