Opioids work by attaching to opioid receptors in the brain, dulling pain, stimulating the reward system in the brain, and increasing the production of the neurotransmitter dopamine which gives the user a euphoric feeling.
The μOR bind enkephalins & beta-endorphin but has low affinity for dynorphins.The μOR exist presynaptically in the periaqueductal gray region, & in the superficial dorsal horn of the spinal cord (substantia gelatinosa of Rolando). μOR are also found in the intestinal tract & cause constipation. Activation of the μ receptor by morphine causes analgesia, sedation, slightly reduced blood pressure, itching, nausea, euphoria, decreased respiration, & miosis. Overdoses can cause circulatory…
Pain Medicine News - µ-Opioid Receptors Impaired in Fibromyalgia Patients, Study Shows
δ-opioid receptor - Wikipedia, the free encyclopedia
The κOR is a type of opioid receptor that binds dynorphin. The κOR may provide a natural addiction control mechanism, & therefore, drugs that act as agonists and increase activation of this receptor may have therapeutic potential in the treatment of addiction. κOR agonists are dysphoric, but dysphoria from κ-opioid receptor agonists has been shown to differ between the sexes.κ-Opioid receptor ligands are also known for their diuretic effects, due to their negative regulation of ADH.