Question

What are the reinforcing and analgesic effects of opioid receptor agonists?

Answer 1

• The analgesic and reinforcing effects of opioids are primarily mediated by mu-opioid receptors (MORs), which are widely-expressed in the central and peripheral nervous systems and in the gastrointestinal tract.Medically, opioids are used for pain relief, but chronic use and abuse can lead to physical dependence.
• Generally, opioid analgesics used in the clinic are ? agonists. These compounds show strongest efficacy in the treatment of severe acute pain, but their activity remains variable in situations of chronic pain.
• In rhesus monkeys, cannabinoids fail to enhance and often decrease self-administration of the mu opioid receptor agonist heroin, suggesting that opioid/cannabinoid mixtures do not have greater reinforcing effects (abuse potential) compared with opioids alone.
• Opioids are potent analgesics for nonvisceral as well as visceral pain. However, µ-opioid receptor agonists commonly cause gastrointestinal side effects such as nausea, vomiting, and constipation. Especially in patients with gastrointestinal disorders, these unwanted effects may become dose limiting.