Endomorphins 1 and 2 are the most selective natural mu-opioid receptor ligands, with potent analgesic activity and distinct pharmacological profiles suggesting different clinical applications.
Most selective natural opioidsEndomorphins have the highest mu-opioid receptor selectivity of any known endogenous opioid — nature's most precise painkillers
What the researchers found
Endomorphins 1 and 2 are the most mu-opioid selective endogenous peptides, with potent analgesia and distinct pharmacological profiles suggesting separate roles in pain modulation and unique therapeutic potential.
Why it matters
Current opioid drugs lack selectivity, causing addiction and side effects. Endomorphins' exceptional mu-selectivity provides a template for designing cleaner, more targeted analgesics.
How the study worked
Comprehensive review of endomorphin discovery, receptor pharmacology, tissue distribution, analgesic properties, and therapeutic implications.
What this study cannot tell us
Endomorphins as peptides have limited stability and bioavailability. Some pharmacological characterizations were still preliminary.
How to read the evidence
Moderate evidence from a comprehensive review of endomorphin pharmacology establishing their unique position among endogenous opioids.
When this study was published
Published in 2002. Endomorphin research has continued, with endomorphin-based drug candidates in various stages of development.
The bigger picture
The opioid crisis demands better painkillers. Endomorphins' mu-selectivity template could guide design of analgesics that match the body's own most selective pain-relieving mechanism.
Questions still open
- Can endomorphin-based drugs achieve oral stability?
- Would endomorphin-selective agonists be less addictive than morphine?
- Why does the body need two different mu-selective endomorphins?
Common questions
What are endomorphins?
Could they lead to better painkillers?
Read the original research
Endomorphins and related opioid peptides.
Vitamins and hormones, 65, 257-79
Citation
Okada, Yoshio; Tsuda, Yuko; Bryant, Sharon D; Lazarus, Lawrence H. (2002). Endomorphins and related opioid peptides.. Vitamins and hormones, 65, 257-79.