A practical reference on Neurotrophic signalling: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-10-13. Anything still debated is marked as such rather than presented as settled.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
The on-call CT squadron is split into four troops, two of which are on immediate notice to move and are restricted to the Hereford-Credenhill area, whilst the other two conduct training and exercises across the UK, but are available for operational deployment should the need arise.
When used during pregnancy, the majority of adverse events caused by acupuncture were mild and transient, with few serious adverse events. The most frequent mild adverse event was needling or unspecified pain, followed by bleeding. Although two deaths (one stillbirth and one neonatal death) were reported, there was a lack of acupuncture-associated maternal mortality. Limiting the evidence as certain, probable or possible in the causality evaluation, the estimated incidence of adverse events following acupuncture in pregnant women was 131 per 10,000. Although acupuncture is not contraindicated in pregnant women, some specific acupuncture points are particularly sensitive to needle insertion; these spots, as well as the abdominal region, should be avoided during pregnancy.
== Epidemiology == Prevalence of disease in a rigorous meta-analysis in 2017 was 46 patients per million. The earliest published prevalence was in 2000 and put at 5 per million. A 2017 study in Ireland reported 112 per million. It is not believed that the disease prevalence is increasing with time, but rather diagnostics and reporting are improving. Estimates of the mean age of onset range from 61 to 68 years old.
Sources: en.wikipedia.org
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After the internal structure of the atom was probed, amateur Dutch physicist Antonius van den Broek proposed in 1913 that the nuclear charge determined the placement of elements in the periodic table. The New Zealand physicist Ernest Rutherford coined the word "atomic number" for this nuclear charge. In van den Broek's published article he illustrated the first electronic periodic table showing the elements arranged according to the number of their electrons. Rutherford confirmed in his 1914 paper that Bohr had accepted the view of van den Broek. The same year, English physicist Henry Moseley using X-ray spectroscopy confirmed van den Broek's proposal experimentally. Moseley determined the value of the nuclear charge of each element from aluminium to gold and showed that Mendeleev's ordering actually places the elements in sequential order by nuclear charge. Nuclear charge is identical to proton count and determines the value of the atomic number (Z) of each element. Using atomic number gives a definitive, integer-based sequence for the elements. Moseley's research immediately resolved discrepancies between atomic weight and chemical properties; these were cases such as tellurium and iodine, where atomic number increases but atomic weight decreases. Although Moseley was soon killed in World War I, the Swedish physicist Manne Siegbahn continued his work up to uranium, and established that it was the element with the highest atomic number then known (92).
Mummies from various dynasties throughout China's history have been discovered in several locations across the country. They are almost exclusively considered to be unintentional mummifications. Many areas in which mummies have been uncovered are difficult for preservation, due to their warm, moist climates. This makes the recovery of mummies a challenge, as exposure to the outside world can cause the bodies to decay in a matter of hours. An example of a Chinese mummy that was preserved despite being buried in an environment not conducive to mummification is Xin Zhui. Also known as Lady Dai, she was discovered in the early 1970s at the Mawangdui archaeological site in Changsha. She was the wife of the Marquis of Dai during the Han dynasty, who was also buried with her alongside another young man often considered to be a very close relative. However, Xin Zhui's body was the only one of the three to be mummified. Her corpse was so well-preserved that surgeons from the Hunan Provincial Medical Institute were able to perform an autopsy. The exact reason why her body was so completely preserved has yet to be determined. Among the mummies discovered in China are those termed Tarim mummies because of their discovery in the Tarim Basin. The dry desert climate of the basin proved to be an excellent agent for desiccation. For this reason, over 200 Tarim mummies, which are over 4,000 years old, were excavated from a cemetery in the present-day Xinjiang region. The mummies were found buried in upside-down boats with hundreds of 13-foot-long wooden poles in the place of tombstones.
Sources: en.wikipedia.org
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.