Semax and Selank are synthetic regulatory peptides developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. Each is a stabilized analog of an endogenous sequence — Semax derived from adrenocorticotropic hormone ACTH(4-10), Selank from the immune peptide tuftsin — engineered with a C-terminal Pro-Gly-Pro extension that resists enzymatic degradation. Both are widely used as tool compounds in preclinical neuroscience for studying neurotrophic signaling, neurotransmitter modulation, and receptor pharmacology.
Semax: Neurotrophic and Melanocortin Signaling
Semax (Met-Glu-His-Phe-Pro-Gly-Pro) is studied primarily for its effect on neurotrophic factor expression. Dolotov et al. reported increased brain-derived neurotrophic factor (BDNF) and TrkB expression in rat hippocampus. Agapova et al. reported increased NGF gene expression in rat hippocampus but decreased NGF gene expression in rat frontal cortex after a single exposure. It also interacts with the melanocortin system via MC4R without significant adrenal steroidogenic activity at the low concentrations used in these models.
Selank: Tuftsin-Derived Modulation
Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is an analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. In preclinical behavioral models it is studied for modulation of GABAergic and serotonergic neurotransmission and for effects on BDNF expression in limbic regions. Its tuftsin lineage also makes it a subject of immunoregulatory research, where the parent sequence influences macrophage and cytokine activity.
Shared Design: Enzymatic Stability
Both peptides illustrate a common medicinal-chemistry strategy: appending a Pro-Gly-Pro motif to a short bioactive sequence to slow proteolytic cleavage and extend the window of central activity in model systems. This makes them useful reference compounds for structure-stability studies of short regulatory peptides.
Research Applications
- Region-specific BDNF/NGF expression assays in rat brain
- Melanocortin (MC4R) and GABAergic receptor pharmacology
- Behavioral neuroscience and memory-consolidation model systems
- Structure-stability studies of proline-capped peptide analogs
References
- Agapova TY, Agniullin YV, Shadrina MI, et al. Neurotrophin gene expression in rat brain under the action of Semax, an analogue of ACTH 4-10. Neurosci Lett 2007. PMID: 17353092. DOI: 10.1016/j.neulet.2007.02.042.
- Dolotov OV, Karpenko EA, Inozemtseva LS, et al. Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Res 2006. PMID: 16996037.
- Manchenko DM, Glazova NIu, Levitskaia NG, et al. Nootropic and analgesic effects of Semax following different routes of administration. Ross Fiziol Zh Im I M Sechenova 2010. PMID: 21268834.
This article summarizes publicly available research for educational purposes and does not constitute medical advice, a therapeutic claim, or a recommendation for human use. Products referenced are sold for laboratory research use only.