This is a working overview of Neurotrophic signalling, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-22 and is reviewed periodically as new material appears.
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.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
A survey in 2007 showed 63% of Americans were overweight or obese, with 26% in the obese category (a BMI of 30 or more). "By 2014, 37.7% of adults in the United States were obese, 35% of men and 40.4% of women (BMI over 40) values were 7.7% for men and 9.9% for women." However, according to world statistics, "American Samoans have the highest BMI (75.6) While Egypt has 43% and Iraq has a BMI of 37.4%." According to the WHO (World Health Organization), obesity has tripled since 1975 and research has shown that obesity is linked to health issues, and high cost of medical care. The Pacific Islands dominate the top obese countries and factors contributed to this problem include dietary change, fast foods, and possible genetic predispositions. The least obese countries include Madagascar, Ethiopia, and Japan. Factors involve a more healthy diet, famine and poverty. WHO and GOO research reports that obesity rates vary by country because of lifestyle, diet and also obesity rates depend on its economic status as well. However, the wealthier the country is, the more educated their citizens tend to be. Promoting a healthier lifestyle is encouraged. The United States being one of the wealthiest countries has the 18th highest obesity rate in the world at 42.7% and researchers attribute that to diet, environment and cultural factors.
=== Dual-flow === Dual-flow, also known as dual, countercurrent chromatography occurs when both phases are flowing in opposite directions inside the column. Instruments are available for dual-flow operation for both Hydrodynamic and hydrostatic CCC. Dual-flow countercurrent chromatography was first described by Yoichiro Ito in 1985 for foam CCC where gas-liquid separations were performed. Liquid–liquid separations soon followed. The countercurrent chromatography instrument must be modified so that both ends of the column have both inlet and outlet capabilities. This mode may accommodate continuous or sequential separations with the sample being introduced in the middle of the column or between two bobbins in a hydrodynamic instrument. A technique called intermittent countercurrent extraction (ICcE) is a quasi-continuous method where the flow of the phases is alternated "intermittently" between normal and reversed-phase elution so that the stationary phase also alternates.
== Biosynthesis == NAAG synthetase activity mediates the biosynthesis of NAAG from glutamate and NAA, but little is known about the mechanism or regulation of this enzyme, and no NAAG synthetase activity has been isolated in cell-free preparations. Since other neuropeptides and nearly all vertebrate peptides are synthesized by post-translational processing, NAAG synthetase activity is relatively unique. As with NAA, the synthesis of NAAG is primarily restricted to neurons, although glial cells also contain and synthesize this peptide. In vitro, NAAG synthesis appears to be regulated by the availability of its precursor, NAA. In addition, during differentiation of neuroblastoma cells, it has been shown that a protein kinase A (PKA) activator will increase the quantity of NAAG, while a protein kinase C (PKC) activator will decrease its concentration. This finding suggests that PKA and PKC have opposing regulatory effects on the NAAG synthetase enzyme.
== Research == A number of potential medical uses for agmatine have been suggested. Agmatine is also used as a prototrophy selection marker in Microbiology for the study of Sulfolobus and Thermococcus genus.
The first state to switch to this method was Ohio, on December 8, 2009. In 2011, after pressure from activist organizations, the manufacturers of pentobarbital and sodium thiopental halted the supply of the drugs to U.S. prisons performing lethal injections and required all resellers to do the same.
Sources: en.wikipedia.org
Tissue remodeling is the reorganization or renovation of existing tissues. Tissue remodeling can be either physiological or pathological. The process of remodeling is generally intended to be the change microscopic properties of a tissue . Remodeling has often the function of optimizing the mechanical properties of the tissue reacting to external stimulus and adapting to it, as it is the case of bone and blood vessel remodeling. Other important examples of tissue that undergo remodeling include: connective tissue under tension or that is undergoing wound healing, during which the Macrophages remodel the tissue by producing extracellular matrix and proteases to modify that specific matrix. Although remodeling happens in tissues that have very different functions, some general patterns can be identified. For those tissue that tend to optimize mechanical properties the cooperation of mechanotransductive components (serving as sensor) that communicate to actuators which will change physically the property (this two parts forming a control loop). This is the case of bone remodelling, where osteocytes perceive the principal direction of the stress applied to the bones and they comunicate it to the osteoblats and osteoclasts that reorient the trabecular structure as to align which such direction to make the tissue have a stiffer response to the strongest solicitations, without increasing weight needlessly (a phenomenon known historically as "Wolf's law").
Notably, about half of her graduate and post-graduate trainees in the past decade have identified as female. She has mentored a next generation of academic faculty in nanomedicine and bioengineering at institutions worldwide. Notable alumni from her lab include:
=== Retesting of samples === According to Article 6.5 in the World Anti-Doping Code samples may be retested later. Samples from high-profile events, such as the Olympic Games, are now retested up to eight years later to take advantage of new techniques for detecting banned substances.
Ford won an 36-seat majority in the 44th Ontario general election. Originally scheduled by election date laws to be held by June 4, 2026, Ford triggered an early provincial election, called a snap election, for February 27, 2025, after meeting with Ontario's lieutenant-governor.
Sources: en.wikipedia.org
=== Border fortification === In a report published in November 2022, the NGO Human Rights Watch found a marked increase in border fortification in a 7.4 kilometres (4.6 mi) long section of the border around Hoeryong. A HRW staff said that the COVID-19 pandemic had been a pretext in building new fences, guard posts and other infrastructure. Fortifications along wider stretches of the border were reported by Reuters in May 2023.
== Further reading == Crippen, T. L. and J. F. Esquivel. (2012). Improved visualization of Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) —Part II: Alimentary canal components and measurements. Psyche 2012, Article ID 607609, 8 pages. Esquivel, J. F., et al. (2012). Improved visualization of Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) — Part I: Morphological features for sex determination of multiple stadia. Psyche 2012, Article ID 328478, 7 pages. Rueda, L. M. and R. C. Axtell. (1996). Temperature-dependent development and survival of the lesser mealworm, Alphitobius diaperinus. Medical and Veterinary Entomology 10(1), 80–86.
High doses of nicotinic acid are also associated with a potential for adverse effects, most commonly a niacin flush reaction that is characterized by redness or flushing of the skin, sensations of heat, itching, and tingling. The nicotinamide vitamer of vitamin B3 does not exhibit the same therapeutic effect for treatment of hypercholesterolemia, but also does not cause a niacin flush reaction and is not associated with the same adverse effects as nicotinic acid.
Combination of small size, ease of engineering, high affinity and specificity makes Affibody molecules suitable alternative as monoclonal antibodies for both molecular imaging and therapeutical applications, especially for the receptor-overexpressing tumors. These proteins are characterized by a high rate of extravasation and rapid clearance of non-bound tracer from the circulation, as well as other nonspecific compartments, when compared to antibodies and their fragments
Kennedy criticized the hearing, saying, "No fair-minded American can believe that he's not qualified—he went to Yale Law School; he didn't get his law degree from Costco. He has a total command of Supreme Court precedent. I think he’s a legal rock star." Kennedy broke from Republicans during the hearing to call for the FBI's investigation into Ford's allegations to be made public. In March 2018, after a dog died in an overhead bin while flying United Airlines, Kennedy said he would file a bill to "prohibit airlines from putting animals in overhead bins" and added that officials "would face significant fines" if they did not comply. That month, he introduced the Welfare Of Our Furry Friends (WOOFF) Act, but the bill died in committee. In July 2018, Kennedy and several other Republican members of Congress met with Russian government officials in Moscow. During the meetings, the two sides discussed election interference, upholding nuclear arms treaties, maintaining peace in Syria, and respecting Ukrainian sovereignty. The delegation was criticized for visiting the country during Fourth of July celebrations and for holding the talks just days after an incident in the United Kingdom in which a couple were poisoned by a suspected Russian nerve agent. On October 12, 2018, the Senate voted to pass Kennedy's Rural Business Investment Program Advisers Relief Act of 2018. The bill removes compliance costs on a venture capital program aimed at stimulating business in rural America. It became law in 2019.
Sources: en.wikipedia.org
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.