This is a working overview of BDNF expression, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-05-02. Anything still debated is marked as such rather than presented as settled.
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.
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide (ACTH fragment analog) | Not a steroid; does not belong to the melanocortin agonist drugs by marketing category |
| Molecular formula | C37H51N9O10S (commonly cited) | Reported values vary slightly with salt and counter-ion content |
| Appearance | White to off-white lyophilized powder | A single batch may appear as a loose cake or fluffy solid |
| Solubility | Freely soluble in water and aqueous buffer | Stock solutions are usually prepared in sterile water or saline |
| Typical storage | −20 °C or below, desiccated and protected from light | Seal opened vials promptly to limit moisture uptake |
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.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
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.
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.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
== See also == Renin-angiotensin system: When the blood flow through the juxtaglomerular apparatus decreases, blood pressure is considered low, and the adrenal cortex secretes aldosterone to increase sodium reabsorption in the collecting duct, thereby increasing blood pressure. Bainbridge reflex: In response to stretching of the right atrium wall, heart rate increases, lowering venous blood pressure. Baroreflex: When the stretch receptors in the aortic arch and carotid sinus increase, the blood pressure is considered to be elevated and the heart rate decreases to lower blood pressure. Antidiuretic hormone: The hypothalamus detects the extracellular fluid hyperosmolality and the posterior pituitary gland secretes antidiuretic hormone to increase water reabsorption in the collecting duct.
SR-15099, also known as SR 2.0, is an atypical opioid and close analogue of SR-17018 and brorphine. It is the analogue of SR-17018 in which the chlorine atom on the benzyl ring has been replaced with a bromine atom. The drug is a non-competitive partial biased agonist of the μ-opioid receptor (MOR) similarly to SR-17018. It has similar effects in animals as SR-17018, such as having robust analgesic effects but producing minimal respiratory depression or hyperlocomotion. SR-15099 was first described in the scientific literature by Laura M. Bohn and colleagues by 2017.
The theatre in Brazil has its origins in the period of Jesuit expansion, when theater was used for the dissemination of Catholic doctrine in the 16th century. In the 17th and 18th centuries, dramatists on the scene of European derivation were for court or private performances. During the 19th century, the playwrights Antônio Gonçalves Dias and Luís Carlos Martins Pena were known for their performance. There were also numerous operas and orchestras. The Brazilian conductor Antônio Carlos Gomes became internationally known with operas such as Il Guarany. At the end of the 19th century, orchestrated dramaturgias were accompanied with songs of famous artists such as the conductress Chiquinha Gonzaga. Already in the early 20th century there was the presence of theaters, entrepreneurs and actor companies. In 1940, Paschoal Carlos Magno and his student's theater, the comedians group and the Italian actors Adolfo Celi, Ruggero Jacobbi and Aldo Calvo, founders of the Teatro Brasileiro de Comédia, renewed the Brazilian theater. From the 1960s, it was attended by a theater dedicated to social and religious issues. The most prominent authors at this stage were Jorge Andrade and Ariano Suassuna.
The team of inventors Edison employed at his laboratories in Menlo Park, New Jersey did, however, develop the first practical light bulb in 1880 (employing a carbonized bamboo filament), shortly prior to Joseph Swan, who invented an even more efficient bulb in 1881 (which used a cellulose filament). Henry Ford did not invent either the automobile or the assembly line. He did improve the assembly line process substantially, sometimes through his own engineering but more often through sponsoring the work of his employees, and he was the main person behind the introduction of the Model T, regarded as the first affordable automobile. Karl Benz (co-founder of Mercedes-Benz) is credited with the invention of the first modern automobile, and the assembly line has existed throughout history. Al Gore never said that he had "invented" the Internet. What Gore actually said was, "During my service in the United States Congress, I took the initiative in creating the Internet", in reference to his political work towards developing the Internet for widespread public use. Gore was the original drafter of the High Performance Computing and Communication Act of 1991, which provided significant funding for supercomputing centers, and this in turn led to upgrades of a major part of the already-existing early 1990s Internet backbone, the NSFNet, and development of NCSA Mosaic, the browser that popularized the World Wide Web.
Both normal "red" marrow and pathologic marrow lesions (such as cancer) are darker than "yellow" marrow on T1-weight sequences, although can often be distinguished by comparison with the MR signal intensity of adjacent soft tissues. Normal "red" marrow is typically equivalent or brighter than skeletal muscle or intervertebral disc on T1-weighted sequences. Fatty marrow change, the inverse of red marrow hyperplasia, can occur with normal aging, though it can also be seen with certain treatments such as radiation therapy. Diffuse marrow T1 hypointensity without contrast enhancement or cortical discontinuity suggests red marrow conversion or myelofibrosis. Falsely normal marrow on T1 can be seen with diffuse multiple myeloma or leukemic infiltration when the water to fat ratio is not sufficiently altered, as may be seen with lower grade tumors or earlier in the disease process.
Sources: en.wikipedia.org
Glucose is an osmotic molecule, and can have profound effects on osmotic pressure in high concentrations possibly leading to cell damage or death if stored in the cell without being modified. Glycogen is a non-osmotic molecule, so it can be used as a solution to storing glucose in the cell without disrupting osmotic pressure.
In summary, about 193 commuter trains turn around in Penn Station during the combined Peak service periods, and 111 commuter trains run-through to West Side or Sunnyside Yards. As both yards are at their practical capacity, any major increase in revenue-to-storage through-running would require major expansion of yard capacity.
Around the 1930s plant nutritionists investigated diseases of certain plants, and thereby, observed symptoms related to existing soil conditions such as salinity or nutrient deficiency. In this context, water culture experiments were undertaken with the hope of delivering similar symptoms under controlled laboratory conditions. This approach forced by Dennis Robert Hoagland led to innovative model systems (e.g., green algae Nitella) and standardized nutrient recipes playing an increasingly important role in modern plant physiology. In 1929, William Frederick Gericke of the University of California at Berkeley began publicly promoting that the principles of solution culture be used for agricultural crop production. He first termed this cultivation method "aquiculture" created in analogy to "agriculture" but later found that the cognate term aquaculture was already applied to culture of aquatic organisms. Gericke created a sensation by growing tomato vines twenty-five feet (7.6 metres) high in his backyard in mineral nutrient solutions rather than soil. He then introduced the term Hydroponics, water culture, in 1937, proposed to him by W. A. Setchell, a phycologist with an extensive education in the classics. Hydroponics is derived from neologism υδρωπονικά (derived from Greek ύδωρ=water and πονέω=cultivate), constructed in analogy to γεωπονικά (derived from Greek γαία=earth and πονέω=cultivate), geoponica, that which concerns agriculture, replacing, γεω-, earth, with ὑδρο-, water.
While de jure not part of West Germany, for Berlin was under the control of the Allied Control Council, West Berlin politically aligned itself with West Germany and was directly or indirectly represented in its federal institutions. The foundation for the influential position held by Germany today was laid during the economic miracle of the 1950s (Wirtschaftswunder), when West Germany rose from the enormous destruction wrought by World War II to become the world's second-largest economy. The first Chancellor Konrad Adenauer, who remained in office until 1963, worked for a full alignment with the NATO rather than neutrality, and secured membership in the military alliance. Adenauer was also a proponent of agreements that developed into the present-day European Union. When the G6 was established in 1975, there was no serious debate as to whether West Germany would become a member. Following the collapse of the Eastern Bloc, symbolised by the opening of the Berlin Wall, both states took action to achieve German reunification. East Germany voted to dissolve and accede to the Federal Republic of Germany in 1990. The five post-war states (Länder) were reconstituted, along with the reunited Berlin, which ended its special status and formed a sixth Land. They formally joined the federal republic on 3 October 1990, raising the total number of states from ten to 16, and ending the division of Germany.
Sources: en.wikipedia.org
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.
It was developed in the Soviet Union during the early 1980s by groups at the Institute of Molecular Genetics in Moscow. Russian approval for intranasal use followed, and it has been marketed there since. Western laboratories encountered it mainly through translated literature and, later, through online research-chemical trade.
It holds a Russian registration as a prescription nasal product but has no approval from the European Medicines Agency or the United States Food and Drug Administration. Buyers outside Russia usually receive material sold strictly for laboratory research. That distinction matters because research-grade and pharmaceutical-grade products carry different documentation and testing expectations.
一般不建议常温长期保存。多数说明指向 -20 °C 冷冻避光。常温运输通常被视为短期可接受，但会加快降解风险。