Which receptor is the primary mediator of analgesia in most opioid analgesics, and what are the implications of mu receptor activation?

Which receptor is the primary mediator of analgesia in most opioid analgesics, and what are the implications of mu receptor activation?

• A. Mu-opioid receptor; activation provides analgesia but also respiratory depression, constipation, miosis, euphoria, sedation, and potential for dependence.
• B. Delta receptor; activation causes sedation only.
• C. Kappa receptor; activation produces analgesia with no side effects.
• D. Gamma receptor; activation causes only respiratory stimulation.

Answer: (A)