β-Funaltrexamine (β-FNA) is an irreversible ( covalently bonding)

opioid antagonist An opioid antagonist, or opioid receptor antagonist, is a receptor antagonist that acts on one or more of the opioid receptors. Naloxone and naltrexone are commonly used opioid antagonist drugs which are competitive antagonists that bind to ...

that was used to create the first

crystal structure In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat ...

of the

μ-opioid receptor The μ-opioid receptors (MOR) are a class of opioid receptors with a high affinity for enkephalins and beta-endorphin, but a low affinity for dynorphins. They are also referred to as μ(''mu'')-opioid peptide (MOP) receptors. The prototypical ...

(MOR). It is selective for antagonism of the MOR over the

δ-opioid receptor The δ-opioid receptor, also known as delta opioid receptor or simply delta receptor, abbreviated DOR or DOP, is an inhibitory 7-transmembrane G-protein coupled receptor coupled to the G protein Gi alpha subunit, Gi/G0 and has enkephalins as it ...

(DOR) and

κ-opioid receptor The κ-opioid receptor or kappa opioid receptor, abbreviated KOR or KOP for its ligand ketazocine, is a G protein-coupled receptor that in humans is encoded by the ''OPRK1'' gene. The KOR is coupled to the G protein Gi/G0 and is one of four re ...

(KOR). Chemically, it is a

naltrexone Naltrexone, sold under the brand name Revia among others, is a medication primarily used to manage alcohol use or opioid use disorder by reducing cravings and feelings of euphoria associated with substance use disorder. It has also been ...

derivative In mathematics, the derivative is a fundamental tool that quantifies the sensitivity to change of a function's output with respect to its input. The derivative of a function of a single variable at a chosen input value, when it exists, is t ...

with a methyl-fumaramide group in the 6-position. In addition to its MOR irreversible antagonism, β-FNA is a reversible

agonist An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...

of the

(KOR) and produces KOR-mediated

analgesic An analgesic drug, also called simply an analgesic, antalgic, pain reliever, or painkiller, is any member of the group of drugs used for pain management. Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in s ...

effects in animals. This has limited its usefulness and contributed to the development of methocinnamox as a more selective functionally irreversible antagonist of the MOR with no significant opioid agonistic actions.

References

Fumarate esters Irreversible antagonists Kappa-opioid receptor agonists Methyl esters Mu-opioid receptor antagonists {{Nervous-system-drug-stub

See also

References