First-ever characterization of the CART neuropeptide in a reptilian brain reveals its wide distribution and regulation by NPY via Y1 receptors, demonstrating that this energy-balance peptide system is conserved across all vertebrate groups.
>93% peptide similarityGecko CART neuropeptide is remarkably conserved compared to rat and human versions, spanning ~350 million years of evolution
What the researchers found
CART neuropeptide was characterized for the first time in a reptilian brain (gecko), showing >93% similarity to mammalian CART peptides and regulation by NPY via Y1 receptors in the hypothalamic arcuate nucleus.
Why it matters
Understanding that CART-NPY interactions controlling energy balance are conserved across all vertebrate groups — from fish to reptiles to mammals — strengthens the evidence that this is a fundamental biological mechanism. This evolutionary perspective can inform therapeutic targeting of appetite-regulating peptide systems.
The numbers in context
The gecko CART cDNA was 683 base pairs. CART-containing neurons were found across multiple brain regions.
How the study worked
Cloned gecko CART cDNA (683 bp). Mapped CART-containing neurons using immunohistochemistry. Used double immunofluorescence to show NPY innervation of CART neurons. Ex vivo hypothalamic slice treatment with NPY and Y1 agonist to test regulation of CART expression.
Who was studied
Hemidactylus leschenaultii geckos
What this study cannot tell us
Single species (gecko) studied. Ex vivo hypothalamic slice experiments may not fully replicate in vivo conditions. The functional consequences of NPY-mediated CART suppression on feeding behavior in geckos were not directly measured. The ventral arcuate CART population was unaffected by NPY, and this differential regulation needs explanation.
How to read the evidence
Preliminary evidence from a single comparative neuroscience study. Well-executed methodology for molecular characterization and neural mapping, but limited to one species.
When this study was published
Published in 2024. Fills a gap in our understanding of neuropeptide conservation across vertebrate evolution.
The bigger picture
The CART and NPY peptide systems are key players in appetite regulation and energy homeostasis. Showing that their interaction is conserved in reptiles — completing the picture across all major vertebrate groups — underscores the fundamental importance of these neuropeptide pathways and validates their relevance as therapeutic targets.
Questions still open
- Why is the ventral arcuate CART population resistant to NPY regulation while dorsal arcuate CART is sensitive?
- Does manipulating CART levels in reptiles produce the same appetite changes seen in mammals?
- Could the remarkable conservation of CART peptide sequence suggest pharmaceutical approaches effective across species?
Common questions
What is CART and what does it do?
Why study a gecko to understand human appetite control?
Read the original research
Cocaine- and Amphetamine-Regulated Transcript Peptide in the Central Nervous System of the Gecko, Hemidactylus leschenaultii: Molecular Characterization, Neuroanatomical Organization, and Regulation by Neuropeptide Y.
The Journal of comparative neurology, 532(10), e25672
Citation
Singh, Omprakash; Basu, Sumela; Srivastava, Abhinav; Pradhan, Dipti R; Dandapat, Pallabi; Bathrachalam, Chandramohan; Singru, Praful S. (2024). Cocaine- and Amphetamine-Regulated Transcript Peptide in the Central Nervous System of the Gecko, Hemidactylus leschenaultii: Molecular Characterization, Neuroanatomical Organization, and Regulation by Neuropeptide Y.. The Journal of comparative neurology, 532(10), e25672. https://doi.org/10.1002/cne.25672