Opiate Drugs, Endogenous Opioids and Related Peptides Opiate drugs are indispensable therapeutic agents in the treatment of severe and chronic pain. Opiates act at receptors normally utilized by members of a family of naturally occurring peptides, the endogenous opioid peptides. Opioid-regulated neurons show very marked adaptations to chronic opiate drug exposure, resulting in the development of tolerance, physical dependence, and addiction.
Different factors regulate the expression of the opioid peptides and their receptors in neurons.
The mechanisms underlying these transcriptional events and the functional significance of changes in the levels of these peptides and their receptors in injury, stress and during chronic drug treatments are now being determined.