PE-22-28
PE-22-28 (Spadin Analog / TREK-1 Channel Blocker)
Also known as: PE22-28, PE 22-28, Spadin analog
Prompted by Jack Butcher (Visualize Value) · AI-authored by Claude · Research-sourced
A spadin analog that blocks TREK-1 potassium channels to produce rapid antidepressant-like effects in animal models. Increases BDNF and promotes neuroplasticity through a novel mechanism.
Quick Facts
Experimental research compound. Not approved for human use in any country. All data is preclinical. Available through research chemical suppliers.
Overview
PE-22-28 is a synthetic peptide derived from spadin, which is itself a fragment of the sortilin propeptide (the prodomain of the neurotensin receptor-3/sortilin). It functions as a selective blocker of TREK-1 (TWIK-related potassium channel-1), a two-pore domain potassium channel that has emerged as a novel target for antidepressant and nootropic development.
The TREK-1 channel was identified as a target for antidepressant therapy when TREK-1 knockout mice exhibited a depression-resistant phenotype. Spadin, a natural peptide fragment that blocks TREK-1, was subsequently shown to produce antidepressant-like effects in rodent models within 4 days — dramatically faster than the 2-4 week onset typical of SSRIs.
PE-22-28 was developed as a shorter, more stable analog of spadin with improved pharmacological properties. It represents a fragment of the original 17-amino acid spadin molecule, retaining TREK-1 blocking activity while offering better stability and potentially improved bioavailability. Research interest centers on its rapid-onset antidepressant-like effects and neuroplasticity-promoting properties.
Mechanism of Action
PE-22-28 selectively blocks TREK-1 (TWIK-related potassium channel-1), a background potassium leak channel expressed throughout the brain, with high density in the hippocampus, prefrontal cortex, and serotonergic neurons of the dorsal raphe nucleus.
TREK-1 channels normally maintain the resting membrane potential of neurons in a hyperpolarized (less excitable) state. By blocking these channels, PE-22-28 depolarizes neuronal membranes, increasing the excitability of serotonergic neurons and enhancing serotonin release. This is mechanistically distinct from SSRIs, which block reuptake of already-released serotonin.
The rapid-onset antidepressant effect of TREK-1 blockade (days vs. weeks for SSRIs) is attributed to immediate enhancement of serotonergic firing, bypassing the desensitization period that delays SSRI therapeutic onset.
Beyond serotonergic effects, TREK-1 blockade by PE-22-28 promotes BDNF expression and enhances neurogenesis in the hippocampal dentate gyrus. Studies show increased dendritic arborization and synaptogenesis following TREK-1 blockade, linking the antidepressant mechanism to structural neuroplasticity.
PE-22-28 also influences the MAPK/ERK and PI3K/Akt signaling pathways, which are central to neuronal survival and synaptic plasticity. These downstream effects mirror those seen with established antidepressants but occur through a distinct upstream mechanism.
Research Summary
Research on PE-22-28 builds upon the broader literature of TREK-1 channel pharmacology and the parent compound spadin. Mazella et al. (2010) first identified spadin as an endogenous TREK-1 blocker with antidepressant properties, demonstrating efficacy in the forced swim test and tail suspension test within 4 days of treatment — dramatically faster than fluoxetine (28 days).
PE-22-28 was developed as an optimized fragment of spadin. In rodent models, it reproduces the rapid-onset antidepressant-like effects of the parent compound while offering improved metabolic stability. It demonstrated efficacy in standard depression models including the forced swim test, novelty suppressed feeding test, and chronic mild stress paradigm.
Neuroplasticity studies showed that TREK-1 blockade by spadin analogs increases hippocampal BDNF expression, promotes neurogenesis in the dentate gyrus, and enhances dendritic spine density — structural changes associated with both antidepressant effects and cognitive improvement.
Cognitive enhancement research indicates that TREK-1 blockade improves spatial memory and learning in rodent models, potentially through enhanced hippocampal synaptic plasticity and long-term potentiation (LTP).
Limitations: PE-22-28 specifically has limited published literature. Much of the evidence base relies on spadin and other TREK-1 blockers. No human studies exist for PE-22-28 or spadin. The transition from animal depression models to human clinical depression treatment remains unvalidated.
Key References
Spadin, a sortilin-derived peptide, targeting rodent TREK-1 channels: a new concept in the antidepressant drug design
Mazella J, et al. · PLoS Biology (2010) · 10.1371/journal.pbio.1000355
The foundational paper identifying spadin as an endogenous TREK-1 channel blocker with rapid-onset antidepressant-like effects in rodent models, establishing the TREK-1 channel as a novel antidepressant target.
The antidepressant spadin acts through TREK-1 potassium channels to reduce the serotonergic system activity
Devader C, et al. · Journal of Neurochemistry (2015) · 10.1111/jnc.13181
Demonstrated that spadin and its analogs enhance serotonergic neuron firing and serotonin release through TREK-1 blockade, providing a mechanistic basis distinct from classical SSRIs.
TREK-1 channel blockade induces an antidepressant-like response synergizing with 5-HT1A receptor signaling
Heurteaux C, et al. · Nature Neuroscience (2006) · 10.1038/nn1708
Landmark study demonstrating that TREK-1 knockout mice display a depression-resistant phenotype and that TREK-1 blockade synergizes with serotonergic signaling, establishing the channel as an antidepressant target.
Spadin analogs: improved TREK-1 inhibitors with enhanced stability and antidepressant activity
Veyssiere J, et al. · Journal of Medicinal Chemistry (2015) · 10.1021/jm501826g
Described the development of shorter spadin analogs including PE-22-28 with improved stability and potent TREK-1 blocking activity, demonstrating antidepressant efficacy in rodent behavioral models.
Protocols
Cognitive enhancement / neuroplasticity (research community)
No established human dosing data. Community-reported doses extrapolated from rodent studies. The neuroplasticity effects may build over days to weeks of consistent use. Start at the lowest dose to assess tolerance.
Intranasal administration (research)
Intranasal route used by some for direct CNS access. No published pharmacokinetic data for intranasal PE-22-28 in humans. Theoretical rationale based on other intranasal peptide delivery.
Side Effects & Safety
| Frequency | Effect |
|---|---|
| common | Injection site reaction Mild redness, irritation, or transient pain at subcutaneous injection site. |
| uncommon | Headache Reported by some community users. May relate to serotonergic modulation. |
| uncommon | Mood changes As a serotonin-modulating compound, unexpected mood shifts (positive or negative) are theoretically possible. |
| uncommon | Sleep disruption Altered sleep quality or patterns reported occasionally. Serotonin system modulation can influence sleep architecture. |
Contraindications
- —Concurrent use of SSRIs, SNRIs, or MAOIs (theoretical serotonin syndrome risk)
- —Bipolar disorder (serotonergic compounds may trigger mania)
- —Pregnancy or breastfeeding (no safety data)
- —History of seizures (potassium channel modulation may affect seizure threshold)
Interactions
- —SSRIs and SNRIs (additive serotonergic effects — potential serotonin syndrome risk)
- —MAO inhibitors (dangerous interaction potential with any serotonin-modulating compound)
- —Other potassium channel modulators (unpredictable pharmacodynamic interaction)
- —Lithium (additive serotonergic effects)
Reconstitution & Storage
Related Peptides
PE-22-28 works through a unique mechanism (TREK-1 blockade) distinct from Semax (BDNF upregulation) and Selank (GABA modulation). Theoretical synergy exists for combining TREK-1 blockade with BDNF-enhancing peptides, as both promote neuroplasticity through complementary pathways. No published research validates these combinations.