Opioid Mu Receptor (MOR)

The opioid mu receptor (μ-opioid receptor, MOR) is a G protein-coupled receptor (GPCR) that plays a central role in the modulation of pain, reward, and addictive behaviors. It is the primary molecular target for both endogenous opioids (such as endorphins and enkephalins) and exogenous opioid drugs including morphine, heroin, fentanyl, methadone, codeine, oxycodone, tramadol, and others. The μ-opioid receptor mediates not only analgesic effects but also many side effects associated with opioid use such as respiratory depression, euphoria, sedation, constipation, tolerance development, physical dependence and addiction.

Other names

Mu receptorMOPOP3MOPropioid receptor mu 1Mu-receptorOPRM1 gene productOpioid Receptor Mu Type

Agonist binding leads to activation of intracellular G proteins or recruitment of β-arrestin proteins, resulting in inhibition of neurotransmitter release by reducing calcium influx into neurons.