Selank

Selank is a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) derived from the sequence of tuftsin — a naturally occurring immunomodulatory tetrapeptide (Thr-Lys-Pro-Arg) produced by enzymatic cleavage of the Fc domain of IgG. Selank was developed by extending the tuftsin sequence with a Pro-Gly-Pro tripeptide, producing a compound with dual anxiolytic and immunomodulatory activity. The anxiolytic mechanism of Selank centres on its modulation of GABAergic signalling — the primary inhibitory neurotransmitter system in the brain. Selank is studied for its effects on GABA receptor expression and function, enhancing inhibitory neurotransmission in brain regions associated with anxiety (amygdala, hippocampus, prefrontal cortex). Unlike benzodiazepine-class anxiolytics that directly agonise GABA-A receptors, Selank appears to modulate GABAergic signalling through upstream mechanisms, including effects on brain-derived neurotrophic factor (BDNF) expression and serotonergic pathway activity. The immunomodulatory mechanism derives from Selank's tuftsin origin: tuftsin is a known immunostimulatory peptide that enhances phagocytic activity of macrophages and neutrophils, and Selank retains immunomodulatory properties, influencing cytokine production and immune cell function. This dual anxiolytic-immunomodulatory profile makes Selank a unique research tool for studying the neuroimmune interface.