Which of the following is NOT a systemic effect of mu receptor activation?

Which of the following is NOT a systemic effect of mu receptor activation?

• A. Antishivering
• B. Miosis
• C. Urinary retention
• D. Nausea and vomiting

Answer: (A)

Mu receptor activation produces a broad set of systemic effects: it causes analgesia, sedation, respiratory depression, miosis, reduced gastrointestinal motility with constipation, urinary retention, and nausea/vomiting via stimulation of the central nervous system and autonomic pathways. Shivering suppression, or antishivering, is not a universal, direct consequence of mu activation. The antishivering effect is not a standard mu-mediated outcome and is more drug-specific (notably with certain opioids like meperidine, which involves additional pharmacologic actions). Thus, antishivering is not considered a general systemic effect of mu receptor activation, whereas miosis, urinary retention, and nausea/vomiting are.

Mu receptor activation produces a broad set of systemic effects: it causes analgesia, sedation, respiratory depression, miosis, reduced gastrointestinal motility with constipation, urinary retention, and nausea/vomiting via stimulation of the central nervous system and autonomic pathways. Shivering suppression, or antishivering, is not a universal, direct consequence of mu activation. The antishivering effect is not a standard mu-mediated outcome and is more drug-specific (notably with certain opioids like meperidine, which involves additional pharmacologic actions). Thus, antishivering is not considered a general systemic effect of mu receptor activation, whereas miosis, urinary retention, and nausea/vomiting are.