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. In rodent hippocampal and cortical tissue, Semax has been reported to upregulate brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and TrkB receptor expression, a signaling axis central to synaptic plasticity research. It also interacts with the melanocortin system via MC4R without significant adrenal steroidogenic activity at the low concentrations used in these models.
A second research line concerns ischemic neuroprotection. In models of induced cerebral ischemia, Semax has been examined for effects on nitric oxide synthase activity, cholinergic signaling, and neuronal survival in the peri-infarct region. These are the endpoints most frequently characterized in the published literature.
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
- BDNF/NGF neurotrophic-factor expression assays
- Ischemic neuroprotection and post-ischemic repair models
- Melanocortin (MC4R) and GABAergic receptor pharmacology
- Behavioral neuroscience and memory-consolidation model systems
- Structure-stability studies of proline-capped peptide analogs
References
- 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.
- Gusev EI, Skvortsova VI, et al. Effectiveness of semax in the acute period of hemispheric ischemic stroke (a clinical and electrophysiological study). Zh Nevrol Psikhiatr Im S S Korsakova 1997. PMID: 11517472.
- 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.