Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity.
Level 5 - mechanism / opinion, no new human data
In vitro radioligand binding study on isolated brain membranes (preclinical bench mechanism study).
PubMed 30255741 · doi:10.2174/0929866525666180925144642
What was done
Researchers investigated the molecular mechanisms of the heptapeptide Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) using radioligand-receptor binding analysis with [3H]GABA on isolated brain cell plasma membranes. High-performance liquid chromatography (HPLC) was used to verify peptide and reagent purity, and binding interactions were evaluated in the presence of Selank alone and in combination with diazepam or olanzapine.
What was found
Selank functioned as a positive allosteric modulator of [3H]GABA binding. When combined with certain benzodiazepines, the modulation of [3H]GABA binding differed from either substance alone and was not cumulative. Selank blocked the modulatory activity of diazepam and olanzapine, indicating distinct but potentially partially overlapping binding sites. The abstract reports no numerical values (such as affinity constants, binding percentages, or concentrations).
Why it matters
This study provides an in vitro mechanistic explanation for Selank's reported anxiolytic properties, indicating that its biological activity involves subtype-selective, concentration-dependent allosteric modulation of GABA receptors rather than direct competition at classical benzodiazepine sites.
Limits
The study is restricted to cell-free in vitro membrane assays, providing no in vivo behavioral or clinical human efficacy data. The abstract provides no quantitative parameters (e.g., Kd, Ki, EC50, sample size of membrane preparations, or statistical variance).
Cited by
- partial Selank promotes calming and enhances restorative deep delta brain waves during sleep.