— Research note —
Semax
Heptapeptide ACTH(4-10) analog developed by the Russian Academy of Sciences investigated for nootropic and neurotrophic research applications.
Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) corresponding to the ACTH(4-7) sequence with a C-terminal Pro-Gly-Pro tripeptide extension. The molecule was developed by the Institute of Molecular Genetics of the Russian Academy of Sciences in the 1980s as part of a research program aimed at identifying short peptide fragments of adrenocorticotropic hormone that retained neurotropic activity while lacking the systemic endocrine effects of the parent hormone. The Pro-Gly-Pro extension confers enzymatic stability and supports intranasal bioavailability, distinguishing semax from earlier ACTH-derived neuropeptides.
In Russian and international research, semax has been characterized as a tool compound for studies of neuroprotection, learning and memory, and brain-derived neurotrophic factor (BDNF) signaling. Preclinical studies in rodent stroke models have reported reductions in infarct volume and improvements in neurological outcomes following administration of the peptide. Mechanistic investigations have identified upregulation of BDNF and nerve growth factor (NGF) expression in hippocampus and cortex as a probable mediator of the observed effects.
The compound has been approved in Russia as a pharmaceutical for ischemic stroke and certain other neurological indications, and is widely used in clinical research within that jurisdiction. Outside Russia, semax has been less extensively studied but appears as a reference compound in academic publications on melanocortin-derived neuropeptide pharmacology and on the broader question of how short peptide fragments can produce sustained neurotrophic effects.
Semax is supplied here for laboratory research use only and is not intended for human consumption. Its primary research applications include cognitive pharmacology, stroke and neuroprotection research models, and structure-activity studies of ACTH-derived neuropeptide fragments.
Mechanism
The molecular mechanism of semax has been investigated in multiple model systems. The peptide does not directly activate the canonical melanocortin receptors with high affinity, distinguishing its pharmacology from that of the parent ACTH or alpha-MSH. Instead, observed effects appear to be mediated through upregulation of BDNF and NGF expression in hippocampus, cortex, and other brain regions, with downstream activation of TrkB receptor signaling and CREB-dependent transcription.
Additional reported mechanisms include modulation of monoaminergic neurotransmission, with effects on dopamine and serotonin systems documented in microdialysis studies. The peptide has also been reported to influence the kallikrein-kinin system and to modulate inflammatory cytokine networks in brain tissue. The Pro-Gly-Pro C-terminal extension stabilizes the molecule against aminopeptidase cleavage and supports the intranasal administration route used in much of the research literature.
Research history
The Russian Academy of Sciences program that produced semax was led by Lev Ashmarin and colleagues at the Institute of Molecular Genetics in Moscow during the 1980s. The molecule emerged from a broader investigation of regulatory peptide fragments derived from ACTH and related neuropeptides. Initial publications appeared in Russian-language journals in the late 1980s and early 1990s, with subsequent English-language disclosures characterizing the pharmacological profile.
Clinical research in Russia advanced the compound through multiple indications, with regulatory approval for ischemic stroke and integration into Russian clinical practice for that and related neurological conditions. Outside Russia, the compound has been less extensively studied but appears in academic publications on neuroprotection, BDNF signaling, and short-peptide neurotrophic pharmacology.
Subsequent research has examined semax in attention and learning paradigms, in optic nerve injury models, and in models of cerebral ischemia. Mechanistic studies have characterized effects on BDNF expression, monoaminergic signaling, and the kallikrein-kinin system. The compound continues to serve as a reference probe for studies of intranasal peptide delivery and for investigations of short-peptide neurotrophic activity, with peer-reviewed publications continuing to appear from Russian and international research groups.
References
- Ashmarin IP, et al. 1995. Semax in the prevention of disease and treatment of cerebrovascular accidents. Zh Nevrol Psikhiatr Im S S Korsakova.
- Dolotov OV, et al. 2006. Semax, an analog of ACTH(4-10), regulates BDNF and trkB expression in the rat hippocampus. Brain Res. PMID: 16678132
- Shadrina MI, et al. 2010. Comparison of the effects of semax and its C-terminal tripeptide PGP on the expression of genes involved in the development of cerebral ischemia. Mol Biol (Mosk). PMID: 21442878
- Medvedeva EV, et al. 2014. Effect of semax and its C-terminal fragment PGP on the expression of VEGF family genes and their receptors in experimental focal ischemia of the rat brain. J Mol Neurosci. PMID: 24585251
- Levitskaya NG, Glazova NY. 2018. Semax: a multimodal melanocortin-derived neuropeptide. Curr Mol Pharmacol.
- Sebentsova EA, et al. 2017. Neuroprotective and neurorestorative effects of semax in models of cerebral ischemia. Bull Exp Biol Med.
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Information presented in third-person scientific context. Research use only. Not medical advice; not for human consumption.