Peptides MEX / Comparisons
Selank vs Semax: sequences and neurobiology models
Selank and Semax are heptapeptides sharing a Pro-Gly-Pro tail, but their first four residues and design origins differ. The cited literature explores GABAergic neurotransmission for Selank and responses to ischemic injury for Semax, without establishing a memory or concentration ranking.
Updated · Sources and editorial standards
| Feature | Selank | Semax |
|---|---|---|
| Sequence[1][2] | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Met-Glu-His-Phe-Pro-Gly-Pro |
| Design origin[1][2] | Tuftsin fragment with PGP extension | ACTH(4–7) fragment with PGP extension |
| Featured models[1][3][2] | Rat cortex and IMR-32 cells | Experimental cerebral ischemia in rats |
A shared tail does not imply the same sequence
Selank combines the tuftsin fragment Thr-Lys-Pro-Arg with Pro-Gly-Pro. Semax combines Met-Glu-His-Phe, corresponding to ACTH(4–7), with the same tail. This partial overlap describes a shared design feature; the complete peptides remain distinct entities.
Selank: results depend on the model
A rat frontal-cortex study examined neurotransmission-related genes after Selank or GABA. In contrast, the 2017 IMR-32 cell study found no direct changes in the assessed genes with Selank alone, although changes occurred in combinations with other substances. This distinction shows why a GABAergic hypothesis needs experimental context.
Semax: ischemia response, not a concentration test
The selected Semax studies analyzed gene and protein expression in rat cerebral-ischemia models. They identified changes in immune, vascular and cellular-injury processes. Measuring those processes in injured tissue is not equivalent to assessing attention, anxiety or cognitive performance in healthy people.
Questions about this reference
Do Selank and Semax share all their amino acids?
No. They share the terminal Pro-Gly-Pro but differ in the first four residues. That distinction is part of molecular identity even though both contain seven residues.
Sources and original reading
- Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission
- Brain Protein Expression Profile Confirms the Protective Effect of the ACTH(4–7)PGP Peptide (Semax) in a Rat Model of Cerebral Ischemia–Reperfusion
- GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells
- The peptide semax affects the expression of genes related to the immune and vascular systems in rat brain focal ischemia: genome-wide transcriptional analysis
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