This is a working overview of BDNF, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-12-31. Anything still debated is marked as such rather than presented as settled.
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。
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
| Property | Value | Notes |
|---|---|---|
| 结构类别 | 线性合成七肽 | 无环化结构，不含二硫键 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | N 端为甲硫氨酸 |
| 分子量 | 约 814 Da | 游离碱形式的计算值 |
| 外观 | 白色至类白色粉末 | 具吸湿性 |
| 溶解性 | 易溶于水 | 亦可溶于甲醇等极性溶剂 |
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
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.
== History == Addition of heated blood to media was first documented for use by Cohen and Fitzgerald in 1910 and then by Dr. Olga Povitzky at the New York City Department of Health Bureau of Laboratories. The term "chocolate" comes from the brown color generated from the higher concentration of heated blood in the mixture and was first used by Warren Crowe in 1915.
Colombia is divided into 32 departments and one capital district, which is treated as a department (Bogotá also serves as the capital of the department of Cundinamarca). Departments are subdivided into municipalities, each of which is assigned a municipal seat, and municipalities are in turn subdivided into corregimientos in rural areas and into comunas in urban areas. Each department has a local government with a governor and assembly directly elected to four-year terms, and each municipality is headed by a mayor and council. There is a popularly elected local administrative board in each of the corregimientos or comunas. In addition to the capital, four other cities have been designated districts (in effect special municipalities), on the basis of special distinguishing features. These are Barranquilla, Cartagena, Santa Marta and Buenaventura. Some departments have local administrative subdivisions, where towns have a large concentration of population and municipalities are near each other (for example, in Antioquia and Cundinamarca). Where departments have a low population (for example Amazonas, Vaupés and Vichada), special administrative divisions are employed, such as "department corregimientos", which are a hybrid of a municipality and a corregimiento. Click on a department on the map below to go to its article.
A method of sunless tanning is consumption of certain carotenoids—antioxidants found in some fruits and vegetables such as carrots and tomatoes—which can result in changes to skin color when ingested chronically and/or in high amounts. Carotenoids are long-lasting. In addition, carotenoids have been linked to a more attractive skin tone (defined as a more golden skin color) than suntan. Carotenes also fulfil the function of melanin in absorbing UV radiation and protecting the skin. For example, they are concentrated in the macula of the eye to protect the retina from damage. They are used in plants both to protect chlorophyll from light damage and harvest light directly. Carotenaemia (xanthaemia) is the presence in blood of the yellow pigment carotene from excessive intake of carrots or other vegetables containing the pigment resulting in increased serum carotenoids. It can lead to subsequent yellow-orange discoloration (xanthoderma or carotenoderma) and their subsequent deposition in the outermost layer of skin. Carotenemia, or carotenoderma, is in itself harmless, and does not require treatment. In primary carotenoderma, when the use of high quantities of carotene is discontinued the skin color will return to normal. It may take up to several months, however, for this to happen.
Sources: en.wikipedia.org
Force amplification in the braking system of most motor vehicles. Used in artesian wells, water towers, and dams. Scuba divers must understand this principle. Starting from normal atmospheric pressure, about 100 kilopascal, the pressure increases by about 100 kPa for each increase of 10 m depth. Usually Pascal's rule is applied to confined space (static flow), but due to the continuous flow process, Pascal's principle can be applied to the lift oil mechanism (which can be represented as a U tube with pistons on either end).
The 1980s brought early radioligand studies for neuroendocrine tumors (NETs) which continued into the early 2000s. In 2017 the European Union (EU) approved the use of radioligand therapy for NETs with the U.S. following close behind in 2018.
== Interactions == The main IGFBP-3 ligands in the circulation are IGF-1 and IGF-2, and the acid-labile subunit (ALS). The serum proteins transferrin, fibronectin, and plasminogen are also known to bind IGFBP-3. In the cell and tissue environment many other interactions have been described (see Table). Two unrelated cell-surface proteins have been designated as IGFBP-3 receptors: low density lipoprotein receptor-related protein 1 (LRP1), also known as alpha-2-macroglobulin receptor or type V TGFβ receptor and the transmembrane protein TMEM219. Both are believed to mediate antiproliferative effects. Functional interactions with the EGF receptor and the type I/type II TGFβ receptor system have also been reported, and other cell-surface proteins such as proteoglycans also bind IGFBP-3. IGFBP-3 can enter cells by both clathrin-mediated and caveolin-mediated endocytosis. possibly involving the transferrin receptor. IGFBP-3 enters the cell nucleus by a mechanism that is incompletely understood, but involves its binding to importin-β. Within the nucleus, it can modulate nuclear hormone receptor activity by direct binding to retinoid X receptor, retinoic acid receptor, vitamin D receptor, PPARγ, and nur77, IGFBP-3 also interacts with DNA-dependent protein kinase within the nucleus to promote the repair of DNA damage. IGFBP3 has been shown to interact with:
Sources: en.wikipedia.org
== Epidemiology == The condition affects adults more frequently than children and males more frequently than females. Most cases occur between the ages of 40 and 60. Polyarteritis nodosa is more common in people with hepatitis B infection.
== Society and culture == Pentobarbital is the INN, AAN, BAN, and USAN, while pentobarbitone is a former AAN and BAN. One brand name for this drug is Nembutal, coined by John S. Lundy, who started using it in 1930, from the structural formula of the sodium salt—Na (sodium) + ethyl + methyl + butyl + al (common suffix for barbiturates). Nembutal is trademarked and manufactured by the Danish pharmaceutical company Lundbeck (now produced by Akorn Pharmaceuticals), which is the only injectable form of pentobarbital approved for sale in the United States. However, European Union restrictions on the export of drugs used to impose the death penalty constrained the availability of the drug in the United States and Canada. Attempts by drug smugglers to transport pentobarbital from Mexico to the United States have been reported since 2018. Ernest H. Volwiler and Donalee L. Tabern developed pentobarbital at Abbott Laboratories in 1930. Abbott discontinued its Nembutal brand of pentobarbital capsules in 1999, largely replaced by the benzodiazepine family of drugs. Abbott's Nembutal, known on the streets as "yellow jackets", was widely abused. They were available as 30, 50, and 100 mg capsules of yellow, white-orange, and yellow colors, respectively. In the 2025 mystery film Wake Up Dead Man, lethal doses of pentobarbital are used as a slow-acting poison in the murder of two separate characters.
The four substrates of the enzyme are carbazole, reduced nicotinamide adenine dinucleotide (NADH), oxygen, and a proton. Its products are 2'-aminobiphenyl-2,3-diol and oxidised NAD+. It is an oxidoreductase that uses molecular oxygen as oxidant and incorporates both its atoms into the starting material. It catalyses the first reaction in the pathway of carbazole degradation.
Sources: en.wikipedia.org
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。
Semax 对应 ACTH 第 4 至第 10 位的片段，并在两端做了替换与延长，使其不再具备促肾上腺皮质激素的典型内分泌活性。这一改动同时改变了它在体内的稳定性与分布特征。
俄罗斯将其列为处方药物，需要医生开具处方。多数其他国家把它当作研究化合物，不能作为药品销售或宣称疗效。具体合法性取决于当地法规。
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.