SEMAX

Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro (C37H51N9O10S, molecular weight 813.9 g/mol, CAS 80714-61-0). Its first four residues reproduce positions 4 to 7 of adrenocorticotropic hormone (ACTH), and a C-terminal Pro-Gly-Pro tripeptide completes the chain, which is why the literature describes it both as an ACTH(4-10) analog and as ACTH(4-7)PGP, a synthetic melanocortin derivative. In degradation studies with cultured nerve cells, its main breakdown products were the pentapeptide His-Phe-Pro-Gly-Pro and the tripeptide Pro-Gly-Pro.

SEMAX in the research literature

Most of the published work on semax deals with neurotrophin signaling in rodent brain. In rats, semax was reported to raise hippocampal BDNF protein about 1.4-fold, with increased TrkB tyrosine phosphorylation and higher levels of exon III BDNF and TrkB mRNA. A time-course study measured NGF and BDNF gene expression in the rat hippocampus, frontal cortex and retina and found region-specific changes, including a rise in retinal BDNF expression at 90 minutes.

In an RNA-Seq study of rats that underwent transient middle cerebral artery occlusion (MCAO), semax exposure was associated with 394 differentially expressed genes. It showed lower expression of inflammation-related genes and higher expression of neurotransmission-related genes. In rat hippocampal slices, semax at 1 micromolar increased the frequency of spontaneous intracellular calcium fluctuations in CA1 pyramidal neurons.