Dynorphin Peptides Identified as the Natural Activators of a Previously Unknown Opioid-Like Receptor
Dynorphin peptides were identified as endogenous ligands for a newly discovered orphan receptor closely related to opioid receptors, expanding our understanding of the opioid peptide system.
Quick Facts
What This Study Found
Dynorphin peptides activate a cloned orphan receptor with high sequence homology to opioid receptors, functioning as its endogenous ligands via G protein-coupled potassium channel activation.
Key Numbers
How They Did This
The orphan receptor was expressed in Xenopus oocytes and mammalian cell lines (CHO-K1, HEK-293). Receptor activation was measured by G protein-activated potassium channel coupling in oocytes and dose-response curves were generated.
Why This Research Matters
Identifying dynorphin as the ligand for this orphan receptor revealed a fourth branch of the opioid receptor system, opening new avenues for pain, addiction, and mood disorder research.
The Bigger Picture
This orphan receptor (later identified as the nociceptin/ORL-1 receptor) became a major research target for developing non-addictive painkillers and treatments for anxiety and depression.
What This Study Doesn't Tell Us
In vitro study using heterologous expression systems. The physiological role of this receptor-ligand interaction in the intact organism was not established in this study.
Questions This Raises
- ?What distinct physiological roles does this orphan receptor serve compared to classical opioid receptors?
- ?Could drugs targeting this receptor provide pain relief without the addiction risk of traditional opioids?
Trust & Context
- Key Stat:
- New receptor identified Dynorphins activate an orphan receptor with high homology to opioid receptors, representing a fourth opioid-like receptor class
- Evidence Grade:
- Strong in vitro evidence with receptor expression in multiple cell systems and clear dose-dependent activation. A landmark pharmacological finding.
- Study Age:
- Published in 1995, this is a landmark receptor identification study. The receptor was later characterized as ORL-1/nociceptin receptor.
- Original Title:
- Identification of dynorphins as endogenous ligands for an opioid receptor-like orphan receptor.
- Published In:
- The Journal of biological chemistry, 270(39), 22772-6 (1995)
- Database ID:
- RPEP-00351
Evidence Hierarchy
Frequently Asked Questions
What is an orphan receptor?
An orphan receptor is a receptor protein whose gene has been identified but whose natural activating molecule (ligand) is unknown. Finding the ligand 'de-orphanizes' the receptor and reveals its biological role.
Why was this discovery important?
It revealed that the opioid peptide system is more complex than previously thought, with at least four receptor types instead of three. This opened new therapeutic targets for pain, addiction, and mood disorders.
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Cite This Study
https://rethinkpeptides.com/research/RPEP-00351APA
Zhang, S; Yu, L. (1995). Identification of dynorphins as endogenous ligands for an opioid receptor-like orphan receptor.. The Journal of biological chemistry, 270(39), 22772-6.
MLA
Zhang, S, et al. "Identification of dynorphins as endogenous ligands for an opioid receptor-like orphan receptor.." The Journal of biological chemistry, 1995.
RethinkPeptides
RethinkPeptides Research Database. "Identification of dynorphins as endogenous ligands for an op..." RPEP-00351. Retrieved from https://rethinkpeptides.com/research/zhang-1995-identification-of-dynorphins-as
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.