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

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

• A. Bradycardia
• B. Analgesia
• C. Respiratory depression
• D. Urinary retention

Answer: (A)

Delta opioid receptor activation mainly provides analgesia through modulation of pain pathways in the CNS and spinal cord, and its other systemic effects are typically less pronounced than those seen with mu receptor activation. The heart rate response is not a hallmark of delta receptor activity; bradycardia is primarily associated with mu agonists, which increase vagal tone and can slow the heart. Therefore, bradycardia would not be expected as a systemic effect of delta receptor activation, making it the correct choice. Analgesia is a classic delta effect, and while respiratory depression and urinary effects can occur with delta stimulation, they are less prominent than with mu agonists.

Delta opioid receptor activation mainly provides analgesia through modulation of pain pathways in the CNS and spinal cord, and its other systemic effects are typically less pronounced than those seen with mu receptor activation. The heart rate response is not a hallmark of delta receptor activity; bradycardia is primarily associated with mu agonists, which increase vagal tone and can slow the heart. Therefore, bradycardia would not be expected as a systemic effect of delta receptor activation, making it the correct choice. Analgesia is a classic delta effect, and while respiratory depression and urinary effects can occur with delta stimulation, they are less prominent than with mu agonists.