Basic opioid function in the reward and regulation pathways
| Opioid | Storage | Stress | Addiction |
|---|---|---|---|
| Dynorphin | •Hypothalamus | •Corticotropin-releasing hormone stimulates dynorphin | •Decreased dopamine release due to binding of DYN at the dopamine receptors (especially nucleus accumbens and dorsal striatum) |
| •Striatum | •Kappa antagonists increase resiliency | ||
| •Hippocampus | •Corticotropin-releasing hormone increases expression of prodynorphin in the hippocampus and nucleus accumbens and blocks glutamatedecreases learning | ||
| •Spinal cord | •Kappa stimulation induces stress-related craving | ||
| Beta-endorphin | •Pituitary (released to blood/periphery) | •Corticotropin-releasing hormone binds presynaptic corticotropin-releasing hormone and mu-opioid receptors that inhibit GABA release, which causes excess release of dopamine | •Increased corticotropin-releasing hormone receptors |
| •Hypothalamus (extended amygdala, mesencephalic reticular formation, periaqueductal gray matter, rostral ventral medulla) | •Corticotropin-releasing hormone and pro-inflammatory cytokine bind lymphocytes and stimulates betaendorphin during inflammation | •Increased corticotropin-releasing hormone release |
DYN: dynorphin
