Selank — Tuftsin Analogue and the GABAergic System in Models

Selank is a synthetic heptapeptide (sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro) designed as a stabilised analogue of tuftsin — a naturally occurring fragment of human immunoglobulin G. Tuftsin, being a short tetrapeptide, undergoes rapid enzymatic degradation in the organism, which limits its usefulness as a research tool. Selank was created by appending a Pro-Gly-Pro fragment, which in the literature is described as an element that increases the molecule's resistance to peptidases. For this reason Selank has become an object of interest as a model neuromodulatory molecule — a tool for studying the links between the immune system and the central nervous system.

Mechanism in brief

If we treat peptides as one of the body's languages — protein fragments acting on a lock-and-key basis toward their targets — Selank is an atypical case. In the preclinical literature it has not been assigned a single, unambiguously identified high-affinity receptor. Instead it is described as a molecule with a pleiotropic action: in research models it has been linked to modulation of the GABAergic system, to effects on enkephalin metabolism (through action on the enzymes that degrade them), and to the expression of genes encoding neurotrophic factors. The starting point of the mechanism remains its kinship with tuftsin, which also links Selank to research on immunological pathways.

What is being studied

The areas below are described solely at the model level — they concern processes observed in vitro and in laboratory animals, not effects in humans.

• GABAergic pathway. In animal behavioural models, the effect of Selank on the expression of GABA receptor subunits and on GABAergic neurotransmission in selected brain structures (including the hippocampus) has been studied. This is the main direction of interest in neuromodulation in the Russian literature.
• Neurotrophic factors. In animal models, changes in the expression of genes associated with neurotrophins, including BDNF, have been analysed as a potential mechanism of influence on neuronal plasticity at the tissue level.
• Enkephalin metabolism and monoamines. In vitro and in animal models, effects on the activity of enzymes degrading enkephalins have been described, as well as changes in monoamine balance (including serotonergic) — as biochemical correlates, not clinical effects.
• Immunological modulation. Owing to its derivation from tuftsin, Selank has also been studied in the context of cytokine and interleukin expression in cellular systems — following the molecule's immunopeptide heritage.

Origin and historical context

Selank was developed in Russia through the collaboration of the Institute of Molecular Genetics of the Russian Academy of Sciences and the Zakusov Institute of Pharmacology. Work on it is part of the Russian school of research on regulatory neuroactive peptides, conducted since the 1990s. The base molecule — tuftsin — was characterised and named in honour of Tufts University, where in the 1970s it was studied as a natural immunomodulatory peptide. Selank is thus an example of an approach in which the starting point for a synthetic analogue is a fragment of an endogenous protein, and the goal is to obtain a more stable tool for research on the neuroimmunological axis.

Research specification

Selank is offered in the form of a lyophilisate (powder after lyophilisation), typical of research peptides on account of its stability during transport and storage under laboratory conditions. In a research context, lyophilised material is stored in accordance with the recommendations for peptides of this class, protecting it from moisture and elevated temperature. The quality standard remains confirmed purity by HPLC together with verification of identity and molecular mass, and each batch should be documented. We make full analytical data and safety documentation available in the safety data sheets section — these parameters describe solely the properties of the research material and do not constitute any information about health applications.

Level of evidence

The available knowledge about Selank comes predominantly from in vitro studies and animal models, published mainly in the preclinical literature. Data concerning humans are limited, and conclusions about mechanisms are of a model-based and correlational nature. The pathways described — GABAergic, neurotrophic and immunological — are the subject of further verification, and many observations require further research, including independent replication and extension beyond laboratory models. Selank should be regarded as a research compound with a promising but incomplete evidence profile.

For research purposes only. Not for consumption by humans or animals.