Ancient Sea Lamprey Brain Reveals Evolutionary Origins of the Gut-Brain Peptide CCK
Mapping CCK-producing neurons in the sea lamprey — one of the oldest living vertebrates — reveals that this gut-brain peptide system has been conserved for over 500 million years of evolution.
Quick Facts
What This Study Found
The sea lamprey CCK-8 peptide is highly similar to mammalian CCK, with CCK neurons distributed across hypothalamus, midbrain, and brainstem regions, and showing the first documented GABA-CCK co-localization in a non-mammalian vertebrate.
Key Numbers
8+ brain regions with CCK neurons; first GABA/CCK co-localization in non-mammal; adult-specific populations
How They Did This
cDNA cloning and sequencing, mRNA in situ hybridization for neuron mapping, custom antiserum generation for immunohistochemistry, and co-localization studies with GABA, glutamate, serotonin, tyrosine hydroxylase, and neuropeptide Y.
Why This Research Matters
Understanding CCK in the most ancient vertebrates reveals which aspects of this gut-brain signaling system are fundamental to all vertebrates, providing evolutionary context for how CCK regulates appetite, digestion, and mood in humans.
The Bigger Picture
The deep conservation of CCK signaling from lampreys to humans suggests this peptide plays such a fundamental role in vertebrate biology that evolution has preserved it largely unchanged for over half a billion years, underscoring its importance in gut-brain communication.
What This Study Doesn't Tell Us
Study is limited to neuroanatomical mapping in one species and does not test CCK function in the lamprey. Differences between larval and adult expression patterns complicate interpretation. Findings may not directly translate to understanding CCK function in mammals.
Questions This Raises
- ?What functional role does GABA-CCK co-expression play in lamprey neurons, and is this co-localization functionally equivalent to mammalian systems?
- ?Does lamprey CCK regulate feeding behavior the same way it does in mammals?
- ?How did CCK signaling diversify as vertebrates evolved jaws and more complex nervous systems?
Trust & Context
- Key Stat:
- 500+ million years CCK peptide structure has been conserved from ancient jawless fish to modern humans — one of the longest-running signaling systems in vertebrate evolution
- Evidence Grade:
- Rated moderate because the study uses rigorous neuroanatomical and molecular techniques with comprehensive brain mapping, though it is descriptive rather than functional.
- Study Age:
- Published in 2020, this study provides foundational evolutionary data about CCK signaling that remains relevant for understanding neuropeptide evolution.
- Original Title:
- Cholecystokinin in the central nervous system of the sea lamprey Petromyzon marinus: precursor identification and neuroanatomical relationships with other neuronal signalling systems.
- Published In:
- Brain structure & function, 225(1), 249-284 (2020)
- Authors:
- Sobrido-Cameán, D, Yáñez-Guerra, L A, Robledo, D, López-Varela, E, Rodicio, M C, Elphick, M R, Anadón, R, Barreiro-Iglesias, Antón
- Database ID:
- RPEP-05143
Evidence Hierarchy
Frequently Asked Questions
What is the sea lamprey and why study its brain?
The sea lamprey is a jawless fish that diverged from other vertebrates over 500 million years ago. Studying its brain reveals which neural systems are ancient and fundamental to all vertebrates, versus those that evolved more recently in mammals.
What is CCK and why does its presence in lampreys matter?
CCK (cholecystokinin) is a peptide that controls appetite, digestion, and anxiety in humans. Finding a nearly identical version in lampreys means this signaling system is incredibly ancient, suggesting it plays a role so essential that evolution has barely changed it.
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Cite This Study
https://rethinkpeptides.com/research/RPEP-05143APA
Sobrido-Cameán, D; Yáñez-Guerra, L A; Robledo, D; López-Varela, E; Rodicio, M C; Elphick, M R; Anadón, R; Barreiro-Iglesias, Antón. (2020). Cholecystokinin in the central nervous system of the sea lamprey Petromyzon marinus: precursor identification and neuroanatomical relationships with other neuronal signalling systems.. Brain structure & function, 225(1), 249-284. https://doi.org/10.1007/s00429-019-01999-2
MLA
Sobrido-Cameán, D, et al. "Cholecystokinin in the central nervous system of the sea lamprey Petromyzon marinus: precursor identification and neuroanatomical relationships with other neuronal signalling systems.." Brain structure & function, 2020. https://doi.org/10.1007/s00429-019-01999-2
RethinkPeptides
RethinkPeptides Research Database. "Cholecystokinin in the central nervous system of the sea lam..." RPEP-05143. Retrieved from https://rethinkpeptides.com/research/sobrido-camean-2020-cholecystokinin-in-the-central
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.