Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity.
Vyunova TV, Andreeva L, Shevchenko K, Myasoedov N, Protein and Peptide Letters, 2018;25(10):914-923
published
- In radioligand binding on isolated brain cell plasma membranes, the peptide was reported to affect [3H]GABA binding as a positive allosteric modulator. Its joint action with certain benzodiazepines regulated [3H]GABA binding in a way the authors describe as not cumulative and different from either substance individually, and the peptide blocked the modulatory activity of diazepam and of olanzapine.
- The authors state their conclusion as a hypothesis they tested and showed: that one molecular mechanism of the peptide can be associated with subtype-selective, concentration-dependent allosteric modulation of GABA receptors. They also note that the peptide's and the benzodiazepines' binding sites are apparently not the same, but may partially overlap.
The two GABA-related records disagree in an informative way. A radioligand study on membrane preparations reports allosteric modulation of GABA binding; a study in a human neuroblastoma cell line reports no change at all in the mRNA levels of 84 GABAergic and neurotransmission genes under the peptide alone. Binding and transcription are different measurements, so neither refutes the other — but a page that showed only the first would read as settled, and it is not.
