opioid receptor subtype delta, member of the class A family of seven-transmembrane G protein-coupled receptors
The delta-opioid receptor binds the endogenous pentapeptide ligands such as enkephalins and produces antidepressant-like effects. The opioid receptor family is composed of four major subtypes: mu (MOP), delta (DOP), kappa (KOP) opioid receptors, and the nociceptin/orphanin FQ peptide receptor (NOP). They are distributed widely in the central nervous system and respond to classic alkaloid opiates, such as morphine and heroin, as well as to endogenous peptide ligands, which include dynorphins, enkephalins, endorphins, endomorphins, and nociceptin. Opioid receptors are coupled to inhibitory G proteins of the G(i/o) family and involved in regulating a variety of physiological functions such as pain, addiction, mood, stress, epileptic seizure, and obesity, among many others.
Comment:Opioid receptors respond to classical opioid alkaloids such as morphine and heroin, as well as to endogenous peptide ligands like dynorphins, enkephalins, endorphins, endomorphins and nociceptin.
Structure:4EJ4: Human delta-opioid receptor binds naltrindole, contacts at 4A.
Comment:also based on the structures of some class A family members with bound ligands (peptides or chemicals), agonists, or antagonists
Comment:Small-molecule chemical ligands tend to bind deeper within the receptor core, compared to a peptide ligand neurotensin, which binds towards the extracellular surface of its receptor.
Jiyao W et al.(2023). "The conserved domain database in 2023.",