Activation of delta-opioid receptors excites spinally projecting locus coeruleus neurons through inhibition of GABAergic inputs.

Stimulation of the noradrenergic nucleus locus coeruleus (LC) releases norepinephrine in the spinal cord, which inhibits dorsal horn neurons and produces analgesia. Activation of this descending noradrenergic pathway also contributes to the analgesic action produced by systemic opioids. The delta-opioid receptors are present presynaptically in the LC… (More)