This is a working overview of BDNF expression, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-20 and is reviewed periodically as new material appears.
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
Identity and purity are commonly assessed by reversed-phase high-performance liquid chromatography, with ultraviolet detection near 214 nanometers for the peptide backbone. Mass spectrometry, either electrospray or matrix-assisted laser desorption, confirms molecular mass and detects truncation or modification products. Amino acid analysis can verify composition. Because the sequence contains no strongly absorbing aromatic residue apart from phenylalanine, detection wavelengths are chosen carefully. Purity values above 95 percent are typical for research-grade material.
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
| Property | Value | Notes |
|---|---|---|
| 化学类别 | 合成七肽 | ACTH(4-10) 结构类似物 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | 单字母写作 MEHFPGP |
| 分子量 | 约 813.9 Da | 随确切形式和盐型略有变化 |
| 常见同义词 | ACTH(4-10) 类似物 | 俄语文献称 Семакс |
| 开发来源 | 俄罗斯 | 二十世纪八十年代 |
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
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.
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.
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.
== History == Alazocine was one of the early members of the benzomorphan family of opioid analgesics to be investigated. It was first described in the scientific literature in 1961. Its development resulted from nalorphine (N-allylnormorphine), a potent analgesic and opioid antagonist with similar pharmacology which had been introduced in the mid-1950s. Alazocine was found to produce strong psychotomimetic effects in humans, and it was not further developed for clinical use. Subsequently, other benzomorphans, such as pentazocine (an N-dimethylallylbenzomorphan), cyclazocine (an N-cyclopropylmethylbenzomorphan), and phenazocine (an N-phenylethylbenzomorphan), were developed, and some have been marketed for use as analgesics. The sigma σ1 receptor was named in 1976 and (+)-alazocine was described as its prototypical ligand. The receptor was initially thought to be an opioid receptor, and then was confused with the NMDA receptor for a time, but was ultimately distinguished from them both. The psychotomimetic effects of alazocine and the other benzomorphans were initially attributed incorrectly to agonism of the σ1 receptor; subsequent research established that the effects are in fact caused by agonism of the κ-opioid receptor and/or antagonism of the NMDA receptor.
== Discovery == Since the 1960s, seryl-tRNA synthetases have been described in various eukaryotic species, in both biochemical and structural analyses. It was not until 1997 that human SARS and its enzyme product were isolated and expressed in Escherichia coli by a team from The European Molecular Biology Laboratory in France.
=== Hopman Cup === Zverev represented Germany at the Hopman Cup for four consecutive years from 2016 through 2019 with three different partners. In 2016, he competed with Sabine Lisicki. The duo won their tie against the French team, with Zverev winning both his singles and mixed doubles matches. However, they were shut out against Great Britain and Australia Green and did not advance to the final. The following year, he entered the competition with Andrea Petkovic. While the pair only won their tie against Great Britain, Zverev also defeated Federer in singles in his first tournament back from injury. Zverev enjoyed more success in 2018 and 2019, pairing with Angelique Kerber. In their first year together, they advanced to the final, primarily on the strength of the pair winning all three of their mixed doubles matches. In the final against Switzerland, Zverev lost his singles match to Federer. Although Kerber won her singles match against Belinda Bencic, they lost the decisive mixed doubles rubber. They returned in 2019 and again reached the final to set up a rematch of the previous year's final with Federer and Bencic. In a round-robin group with Australia, France, and Spain, the two of them won all six of their singles matches, but lost two of their three mixed doubles matches against Australia and France. Like the previous year, the final was decided by the mixed doubles match after Federer defeated Zverev and Kerber defeated Bencic. With the Fast4 format, the match went to three sets. In the third set tiebreak, both teams had a match point at 4–4.
Sources: en.wikipedia.org
=== Pharmacokinetics === The oral bioavailability of setipiprant is 44% in rats and 55% in dogs, which suggests that it should be orally bioavailable in humans. The half-life of setipiprant in humans is about 11 hours. The maximum concentration in plasma (Cmax) is 6.04 and 6.44 mcg/mL for setipiprant tablets and capsules respectively, with an area under the curve of 31.88 and 31.50 mcg×hours/mL for setipiprant tablets and capsules respectively. Cmax was reached between 1.8–4 hours after oral administration. The tablet and capsule formulations are bioequivalent.
While uterine prolapse is rarely life-threatening, the symptoms associated with uterine prolapse can have a significant impact on quality of life. The severity of prolapse symptoms does not necessarily correlate with the degree of prolapse, and one may experience little to no bothersome symptoms with even advanced prolapse. Additionally, different forms of pelvic organ prolapse often present with similar symptoms. Most women who experience pelvic organ prolapse do not have symptoms. When symptoms are present, the most common and most specific symptoms for uterine prolapse—and organ prolapse in general—into the vagina are bulge symptoms, such as pelvic pressure, vaginal fullness, or a palpable vaginal bulge, and these symptoms are often more common and more severe if the prolapse reaches the vaginal hymen. Urinary symptoms, such as uncontrollable loss of urine or difficulty urinating, may also be present. Complete uterine prolapse in which the uterus protrudes through the vaginal hymen is known as procidentia. In the absence of treatment, symptoms of procidentia may include purulent vaginal discharge, ulceration, and bleeding. Complications of procidentia include urinary obstruction. People may also report sexual dysfunction symptoms, such as pain with sexual intercourse and decreased libido. There is conflicting data concerning the effect of pelvic organ prolapse on sexual function. The severity of the symptoms associated with prolapse seems to have a negative effect on sexual activity and reported satisfaction.
People in Sanlúcar historically worked primarily in agriculture (mainly viticulture) and fishing (especially for the famous Sanlúcar prawn). These two occupations were naturally concentrated in different parts of the town, and until the modernizing trends of the last few decades, there were marked distinctions between the people living in each area. People living near the sea, in the area known as Bajo de Guía, were almost exclusively dedicated to fishing. Now these same people combine fishing with managing restaurants that rely on fresh fish and shellfish for their menus. People living in the higher elevations away from the sea, in a part of the town known as the Barrio Alto, formerly dedicated themselves exclusively to agriculture. However, with the advent of mechanisation this sector requires less manpower throughout the year, and most farm workers now work only seasonally during the grape harvest, in the so-called "sherry triangle". The centre of Sanlúcar developed as a commercial hub, with a cityscape of intermixed historic buildings (monasteries, churches, etc.) and more modern ones. This part of the city developed at the beginning of the 20th century as the neighbourhood of the bourgeoisie and the aristocracy. Sanlúcar was then a popular beach resort; presently the people living in this area are generally linked to local wine-making interests and the tourist industry.
Sources: en.wikipedia.org
Announced tests: The athletes know when they are tested. Unannounced tests: Athletes don't know when they are tested. These tests are the effective ones when they are conducted outside of the competition periods.
== Background == During the Busan Summit on October 30, 2025, US president Donald Trump invited Chinese leader Xi Jinping to visit the United States at an appropriate time. During his May 2026 state visit to China, Trump invited Xi to the White House in September. On July 23, Trump said that Xi would be visiting on 24 September. On September 4, Reuters reported that Xi would be travelling with a large business delegation. However, The Wall Street Journal reported on September 22 that Xi was unlikely to bring a business delegation. This was Xi's first visit to the White House after 11 years. The state dinner was also the second one held during the second Trump administration, following the one held for King Charles III during his state visit in April 2026. On September 20, 2026, Chinese vice premier He Lifeng met with US secretary of treasury Scott Bessent and Trade Representative Jamieson Greer in New York City, where they agreed to set up an AI dialogue. On September 21, the Chinese foreign ministry announced that Xi would pay a state visit to the US from September 23 to 25. The ministry spokesperson Guo Jiakun said that two heads of state's reciprocal visits within a six-month period are "of historic, milestone significance". On September 23, Chinese ambassador to the US Xie Feng wrote an article in the People's Daily, saying China and the US should manage their differences in good faith, and that the US should stop fabricating pretexts such as national security, economic imbalances and forced labor in trying to constrain China.
Celloscope automated cell counter was developed in the 1950s for enumeration of erythrocytes, leukocytes, and thrombocytes in blood samples. Together with the Coulter counter, the Celloscope analyzer can be considered one of the predecessors of today's automated hematology analyzers, as the principle of the electrical impedance method is still utilized in cell counters installed in clinical laboratories around the world.
Shorter polysaccharides, with 3 to 10 monomers, are called oligosaccharides. A fluorescent indicator-displacement molecular imprinting sensor was developed for discriminating saccharides. It successfully discriminated three brands of orange juice beverage. The change in fluorescence intensity of the sensing films resulting is directly related to the saccharide concentration.
Sources: en.wikipedia.org
不是。Semax 是完全人工合成的七肽，自然界中没有对应的已知肽段。它的设计灵感来自促肾上腺皮质激素片段 ACTH(4-10)，但序列经过了替换和延长。
Semax 被描述为 ACTH(4-10) 的结构类似物，两者共享部分序列特征。它保留了该片段的部分神经相关活性方向，但去除了完整片段带来的激素释放效应。二者并非同一物质，也不能互相替代。
加入的 Pro-Gly-Pro 三肽被普遍认为能提升分子对蛋白水解酶的稳定性。这种设计让短肽在体内维持时间更长。具体延长的程度以及不同组织中是否一致，文献中仍存在不同报告。
Solid peptide is best kept frozen at about minus 20 degrees Celsius in a sealed container with desiccant. It should be allowed to reach room temperature before opening to prevent condensation. Repeated warming and cooling of the same vial is discouraged.