Mu-delta opioid receptor heteromer (MOR-DOR heteromer)

The Mu-delta opioid receptor heteromer represents a molecular complex formed by physical interaction between MOR and DOR, both of which are class A G protein-coupled receptors highly expressed in the central and peripheral nervous system. This heteromer exhibits unique ligand binding, signaling, and trafficking properties compared to its monomeric counterparts. It plays a role in pain perception, reward, and addictive behaviors. Selective targeting of MOR-DOR heteromers with bivalent or heteromer-preferring drugs offers the potential for novel analgesics with reduced tolerance, dependence, and addictive potential. Despite promising behavioral and pharmacological data in preclinical models, its detailed mechanisms and therapeutic profile (including safety and biomarker strategies) remain to be fully established. The concept of opioid receptor heteromerization adds complexity to opioid pharmacology and presents an innovative avenue for modulating opioid effects

Other names

MOR-DOR heteromerMu/delta opioid receptor heteromerDOR/MOR heteromerMu opioid receptor-delta opioid receptor heteromerMu-delta OR heteromer

Bivalent ligands: Simultaneous binding to MOR and DOR within the heteromer alters classical opioid signaling, leading to analgesia with reduced tolerance and dependence Allosteric modulation: Ligand binding to one protomer can influence affinity and signaling of the partner protomer Agonism: Selective agonists (e.g., CYM51010) activate heteromeric signaling pathways Antagonism: Some ligands (e.g., Naltrindole in conjunction with MOR agonists) selectively block DOR function within the heteromer, altering analgesic/tolerance profile