TLQP-62: A Brain Peptide That Produces Rapid Antidepressant Effects in Mice
The VGF-derived neuropeptide TLQP-62 rapidly reversed depression-like behavior in mice by activating the same TrkB/mTOR signaling pathway used by ketamine.
Quick Facts
What This Study Found
The neuropeptide fragment TLQP-62, derived from the VGF protein, produced rapid antidepressant-like effects when administered directly into the prefrontal cortex of mice. It also reversed depression-like behaviors caused by chronic social defeat stress — a validated mouse model of depression.
The mechanism was traced to a specific signaling cascade: TLQP-62 activates the TrkB receptor (the BDNF receptor), which triggers mTOR signaling, decreases the gene BICC1, and increases synaptic proteins including the AMPA receptor GluA1 subunit. When researchers blocked TrkB with the antagonist ANA-12, all of TLQP-62's antidepressant effects were abolished — confirming TrkB as the essential starting point of the cascade.
Key Numbers
TLQP-62 infused into PFC · Rapid antidepressant effects · Reversed CSDS-induced depression · TrkB/mTOR/BICC1 signaling pathway · GluA1 phosphorylation at Ser845 · Effects abolished by TrkB antagonist ANA-12
How They Did This
Mouse study using two depression models: acute behavioral tests and chronic social defeat stress (CSDS). TLQP-62 was administered directly into the prefrontal cortex. Researchers measured behavioral outcomes, signaling proteins (TrkB, mTOR, BICC1, GluA1), and phosphorylation states. The TrkB antagonist ANA-12 was used to confirm mechanism specificity.
Why This Research Matters
Most antidepressants take weeks to work. TLQP-62 produces rapid antidepressant effects through a pathway that overlaps with ketamine's mechanism (TrkB/mTOR/synaptic protein synthesis). This suggests VGF-derived peptides could represent a new class of fast-acting antidepressants that work through the brain's own neurotrophic system rather than targeting serotonin or other monoamines.
The Bigger Picture
The discovery that ketamine produces rapid antidepressant effects through TrkB/mTOR signaling revolutionized depression research. TLQP-62 appears to tap into this same pathway but through the brain's own neuropeptide system. If VGF-derived peptides can be made to reach the brain from a practical route of administration, they could offer rapid antidepressant effects without ketamine's dissociative side effects and abuse potential.
What This Study Doesn't Tell Us
Animal study only — no human data. TLQP-62 was delivered directly into the brain, which isn't a viable clinical route. The peptide's ability to cross the blood-brain barrier from systemic administration is unknown. Male mice only. The chronic social defeat stress model, while validated, doesn't fully capture human depression.
Questions This Raises
- ?Can TLQP-62 or similar VGF-derived peptides cross the blood-brain barrier when given systemically?
- ?How do the antidepressant effects of TLQP-62 compare to ketamine in head-to-head studies?
- ?Are VGF peptide levels altered in people with depression, and could they serve as biomarkers?
Trust & Context
- Key Stat:
- Rapid antidepressant effect via TrkB/mTOR pathway TLQP-62 activated the same brain signaling cascade that makes ketamine a fast-acting antidepressant — but through the brain's own neuropeptide system rather than an external drug.
- Evidence Grade:
- Rated low: well-designed animal mechanistic study with clear pathway delineation, but no human data. Direct brain injection limits translational relevance. Male mice only.
- Study Age:
- Published in 2018. VGF-derived peptide research has continued to expand, with ongoing investigation into their antidepressant potential and delivery challenges.
- Original Title:
- Mechanisms underlying the rapid-acting antidepressant-like effects of neuropeptide VGF (non-acronymic) C-terminal peptide TLQP-62.
- Published In:
- Neuropharmacology, 143, 317-326 (2018)
- Authors:
- Lv, Dan, Chen, Yaping, Shen, Mengxin, Liu, Xu, Zhang, Yanhua, Xu, Jiangping, Wang, Chuang
- Database ID:
- RPEP-03793
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
What is TLQP-62 and how does it fight depression?
TLQP-62 is a peptide fragment naturally derived from a brain protein called VGF. It works by activating the TrkB receptor in the prefrontal cortex — the brain region involved in mood regulation — which triggers a cascade of signaling that strengthens synaptic connections. This is similar to how ketamine produces its rapid antidepressant effects.
Could TLQP-62 become an antidepressant medication?
It's a long way off. The peptide was injected directly into mouse brains in this study, which isn't practical for human treatment. Researchers would need to find a way to deliver it to the brain through conventional routes like injection or oral dosing, and then prove it works and is safe in humans.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-03793APA
Lv, Dan; Chen, Yaping; Shen, Mengxin; Liu, Xu; Zhang, Yanhua; Xu, Jiangping; Wang, Chuang. (2018). Mechanisms underlying the rapid-acting antidepressant-like effects of neuropeptide VGF (non-acronymic) C-terminal peptide TLQP-62.. Neuropharmacology, 143, 317-326. https://doi.org/10.1016/j.neuropharm.2018.09.046
MLA
Lv, Dan, et al. "Mechanisms underlying the rapid-acting antidepressant-like effects of neuropeptide VGF (non-acronymic) C-terminal peptide TLQP-62.." Neuropharmacology, 2018. https://doi.org/10.1016/j.neuropharm.2018.09.046
RethinkPeptides
RethinkPeptides Research Database. "Mechanisms underlying the rapid-acting antidepressant-like e..." RPEP-03793. Retrieved from https://rethinkpeptides.com/research/lv-2018-mechanisms-underlying-the-rapidacting
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.