Opioids analgesia is produced by stimulating which receptors?

Opioids analgesia is produced by stimulating which receptors?

• A. NMDA receptors
• B. Opioid receptors
• C. GABA receptors
• D. Serotonin receptors

Answer: (B)

Opioid analgesia arises when opioids activate opioid receptors, especially the mu receptors, in the brain and spinal cord. These receptors are Gi/o-coupled, so their activation lowers cellular excitability by reducing cAMP, increasing potassium efflux to hyperpolarize neurons, and decreasing calcium influx to presynaptic terminals. This dampens the release of excitatory transmitters like substance P and glutamate, diminishing nociceptive signal transmission in the dorsal horn. Activation of opioid receptors in the brain also engages descending inhibitory pathways, further boosting analgesia. Other receptor types (NMDA, GABA, serotonin) are not the primary targets for opioid analgesia, though they can influence pain processing in other ways.

Opioid analgesia arises when opioids activate opioid receptors, especially the mu receptors, in the brain and spinal cord. These receptors are Gi/o-coupled, so their activation lowers cellular excitability by reducing cAMP, increasing potassium efflux to hyperpolarize neurons, and decreasing calcium influx to presynaptic terminals. This dampens the release of excitatory transmitters like substance P and glutamate, diminishing nociceptive signal transmission in the dorsal horn. Activation of opioid receptors in the brain also engages descending inhibitory pathways, further boosting analgesia. Other receptor types (NMDA, GABA, serotonin) are not the primary targets for opioid analgesia, though they can influence pain processing in other ways.