Blocking Enzymes That Destroy Natural Painkillers Boosts Pain Relief From Acupuncture and Opioid Peptides
A peptidase inhibitor cocktail enhanced pain relief from met-enkephalin, beta-endorphin, and electroacupuncture, but not from dynorphin — revealing peptide-specific enzyme vulnerabilities.
Quick Facts
What This Study Found
Peptidase inhibitor mixture enhanced antinociception from met-enkephalin, beta-endorphin, and electroacupuncture, but not dynorphin-(1-13).
Key Numbers
How They Did This
Rats received intrathecal injections of the peptidase inhibitor mixture (amastatin, captopril, phosphoramidon) followed by opioid peptides or electroacupuncture at the Hoku point. Pain threshold was measured by hind paw pressure test.
Why This Research Matters
The body makes its own painkillers (opioid peptides) but enzymes break them down quickly. This study shows that blocking those enzymes can dramatically improve natural pain relief, pointing toward a drug strategy that works with the body rather than replacing its signals.
The Bigger Picture
Instead of giving people opioid drugs, we could boost their own natural painkillers by blocking the enzymes that destroy them. This is potentially a non-addictive approach to pain management.
What This Study Doesn't Tell Us
Animal study in rats using spinal injection. The enzyme inhibitors were given directly into the spinal canal, not by mouth. The combination approach has not been tested in humans.
Questions This Raises
- ?Could peptidase inhibitors be developed as non-addictive pain medications?
- ?Why is dynorphin resistant to this enzyme inhibitor combination?
Trust & Context
- Key Stat:
- Acupuncture enhanced too The enzyme inhibitors boosted electroacupuncture analgesia, proving acupuncture works partly through endogenous opioid peptides
- Evidence Grade:
- Moderate — animal study with multiple comparisons and a revealing dissociation between peptide types.
- Study Age:
- Published in 1994 (32 years ago). Dual enkephalinase inhibitors have since been developed and tested in humans.
- Original Title:
- Effects of a mixture of peptidase inhibitors (amastatin, captopril and phosphoramidon) on Met-enkephalin-, beta-endorphin-, dynorphin-(1-13)- and electroacupuncture-induced antinociception in rats.
- Published In:
- Japanese journal of pharmacology, 66(3), 337-45 (1994)
- Authors:
- Kishioka, S(3), Miyamoto, Y(2), Fukunaga, Y, Nishida, S, Yamamoto, H
- Database ID:
- RPEP-00299
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
How does blocking enzymes help with pain?
Your body constantly produces natural painkillers (opioid peptides), but enzymes rapidly break them down. Blocking those enzymes lets your natural painkillers last longer and work better — enhancing your own pain relief system.
Is this related to how acupuncture works?
Yes — the enzyme inhibitors also enhanced acupuncture's pain-relieving effect, confirming that acupuncture triggers the release of endogenous opioid peptides. Protecting those peptides from breakdown makes acupuncture more effective.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-00299APA
Kishioka, S; Miyamoto, Y; Fukunaga, Y; Nishida, S; Yamamoto, H. (1994). Effects of a mixture of peptidase inhibitors (amastatin, captopril and phosphoramidon) on Met-enkephalin-, beta-endorphin-, dynorphin-(1-13)- and electroacupuncture-induced antinociception in rats.. Japanese journal of pharmacology, 66(3), 337-45.
MLA
Kishioka, S, et al. "Effects of a mixture of peptidase inhibitors (amastatin, captopril and phosphoramidon) on Met-enkephalin-, beta-endorphin-, dynorphin-(1-13)- and electroacupuncture-induced antinociception in rats.." Japanese journal of pharmacology, 1994.
RethinkPeptides
RethinkPeptides Research Database. "Effects of a mixture of peptidase inhibitors (amastatin, cap..." RPEP-00299. Retrieved from https://rethinkpeptides.com/research/kishioka-1994-effects-of-a-mixture
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.