Dynorphin Opioid Peptides Found in Lizard, Turtle, and Alligator Brains
All four dynorphin-family peptides were detected in the brains of reptiles from three major lineages, showing this opioid system is at least 300 million years old.
Quick Facts
What This Study Found
All four prodynorphin end products detected in turtle, lizard, and alligator brains by radioimmunoassay and chromatography.
Key Numbers
How They Did This
Brain acid extracts from Pseudemys scripta (turtle), Anolis carolinensis (lizard), and Alligator mississippiensis were fractionated by gel filtration and analyzed by radioimmunoassay.
Why This Research Matters
Finding dynorphin peptides in all major reptile lineages establishes that the prodynorphin system is ancient and was present before reptiles and mammals diverged.
The Bigger Picture
The dynorphin system isn't a recent mammalian innovation — it's an ancient brain system shared across vertebrates. This evolutionary conservation implies it serves fundamental biological functions that have been maintained for hundreds of millions of years.
What This Study Doesn't Tell Us
Heterologous mammalian antibodies used, which may not perfectly detect reptilian peptide variants. Only whole brain extracts analyzed, not regional distribution.
Questions This Raises
- ?Are dynorphin functions similar in reptiles and mammals?
- ?When in vertebrate evolution did the different opioid peptide families first arise?
Trust & Context
- Key Stat:
- 3 orders, all positive Dynorphin peptides detected in all three major reptile lineages — suggesting conservation since before the reptile-mammal split
- Evidence Grade:
- Preliminary — uses mammalian antibodies to detect reptilian peptides, which may underestimate actual levels. Detection was positive but quantitative accuracy uncertain.
- Study Age:
- Published in 1992 (34 years ago). Subsequent genomic studies have confirmed the ancient origins of opioid peptide gene families.
- Original Title:
- Detection of prodynorphin end products in lizard, turtle, and alligator brain extracts.
- Published In:
- Peptides, 13(3), 435-40 (1992)
- Authors:
- Goldsmith, A M, Sei, C A(3), Lance, V, Dores, R M
- Database ID:
- RPEP-00232
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
Why look for opioid peptides in reptile brains?
By checking whether reptiles have the same opioid peptides as mammals, scientists can determine how old these systems are. If all major reptile groups have dynorphins, the system must predate the reptile-mammal evolutionary split.
How old is the dynorphin system?
Since reptiles and mammals diverged over 300 million years ago and both have dynorphin peptides, this opioid system is at least that old — meaning it serves functions so important that evolution has preserved it across vastly different species.
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Cite This Study
https://rethinkpeptides.com/research/RPEP-00232APA
Goldsmith, A M; Sei, C A; Lance, V; Dores, R M. (1992). Detection of prodynorphin end products in lizard, turtle, and alligator brain extracts.. Peptides, 13(3), 435-40.
MLA
Goldsmith, A M, et al. "Detection of prodynorphin end products in lizard, turtle, and alligator brain extracts.." Peptides, 1992.
RethinkPeptides
RethinkPeptides Research Database. "Detection of prodynorphin end products in lizard, turtle, an..." RPEP-00232. Retrieved from https://rethinkpeptides.com/research/goldsmith-1992-detection-of-prodynorphin-end
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.