description
Opioids are chemical substances similar to opiates, the active substances found in opium (morphine, codeine etc.). Opioid action is mediated by the receptors for endogenous opioids; peptides such as the enkephalins, the endorphins or the dynorphins. Opioids possess powerful analgesic and sedative effects, and are widely used as pain-killers. Their main side-effect is the rapid establishment of a strong addiction. Opioids receptors are G-protein coupled receptors (GPCR). There are four classes of receptors: mu (MOR), kappa (KOR) and delta (DOR), and the nociceptin receptor (NOP)

external resources
NCBI:1269584
REACTOME:R-HSA-111885
PUBMED:9422713
PUBMED:9218123
PUBMED:16612131

genes
ADCY1 , ADCY2 , ADCY3 , ADCY5 , ADCY6 , ADCY7 , ADCY8 , ADCY9 , GRK2 , CALM1 , CALM2 , CALM3 , CAMK4 , CDK5 , CREB1 , GNAI1 , GNAI2 , GNAI3 , GNAL , GNAO1 , GNAT1 , GNAT2 , GNAZ , GNB1 , GNB2 , GNB3 , GNG3 , GNG4 , GNG5 , GNG7 , GNG10 , GNG11 , GNGT1 , GNGT2 , ITPR1 , ITPR2 , ITPR3 , OPRM1 , PDE1A , PDE1C , PDE4A , PDE4B , PDE4C , PDE4D , PDE1B , PDYN , PLA2G4A , PLCB2 , PLCB3 , PLCB4 , POMC , PPP1CA , PPP2CA , PPP2CB , PPP2R1A , PPP2R1B , PPP2R5D , PPP3CA , PPP3CB , PPP3CC , PPP3R1 , PRKACA , PRKACB , PRKACG , PRKAR1A , PRKAR1B , PRKAR2A , PRKAR2B , PRKCA , PRKCD , PRKCG , MAPK1 , GNB5 , AHCYL1 , PLCB1 , GNG13 , GNG2 , GNG12 , GNB4 , PPP1R1B , GNG8 , ADCY4 , GNAT3 , MIR197 , LOC729966 ,