The short version of Semax fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-07-30. Anything still debated is marked as such rather than presented as settled.
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 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 |
|---|---|---|
| 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 |
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.
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.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
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.
The equilibrium constant for this dissociation reaction is known as a dissociation constant. The liberated proton combines with a water molecule to give a hydronium (or oxonium) ion H3O+ (naked protons do not exist in solution), and so Arrhenius later proposed that the dissociation should be written as an acid–base reaction:
Humans with loss-of-function mutations in the PIEZO2 gene exhibit specific deficits in joint proprioception, as well as vibration and touch discrimination, suggesting that the PIEZO2 channel is essential for mechanosensitivity in some proprioceptors and low-threshold mechanoreceptors. Although it was known that finger kinesthesia relies on skin sensation, recent research has found that kinesthesia-based haptic perception relies strongly on the forces experienced during touch. This research allows the creation of "virtual", illusory haptic shapes with different perceived qualities.
== Government, law, and military == Captain of the Parish, a (now mainly ceremonial) appointment in the Isle of Man (post-nominal letters CP) Central Powers, a military alliance before and during World War I, led by the German Empire Certified Paralegal, an American legal qualification Charterparty, a maritime contract for the hire of a ship Civil parish, the lowest tier of government in England Command Post, in military terminology Commissioner of Police, the top-ranking officer of the Police Force Communist party, a political party that advocates communism through state policy Consejo popular, an electoral ward of Cuba Montenegrin Party (Crnogorska partija), a political party in Serbia
Sources: en.wikipedia.org
For example, γδ T cells express a T-cell receptor comprising γ and δ chains instead of the α and β chains that conventional T cell receptors use, and they are able to recognize antigen without the need for presenting it on MHC proteins (though some have shown the ability to recognize MHC-presented antigens), instead having a mode of recognition that resembles that of antibodies, or recognizing phosphoantigens (antigens that are phosphorylated) through butyrophilin. Mucosa-associated invariant T cells (MAIT) cells recognize ligands presented by the MHC-related protein MR1, which presents metabolites of riboflavin, pyridoxine, and folates. NKT cells recognize glycolipid antigens presented on CD1d, most prominently α-galactosylceramide. In contrast to T cell receptors, antibodies can recognize any type of molecule at virtually any size and can recognize either linear or conformational epitopes (the amino acids that comprise an epitope do not need to be next to each other in the primary structure but do need to be near one another when the protein is folded). At the molecular level, an antigen can be characterized by its ability to bind to an antibody's paratopes. Different antibodies have the potential to discriminate among specific epitopes present on the antigen surface.
X-rays can be passed through the body and used in medical radiography and fluoroscopy to differentiate interior structures that have varying degrees of opaqueness. Magnetic resonance imaging, computed tomography, and ultrasound imaging have all enabled the examination of internal structures in unprecedented detail to a degree far beyond the imagination of earlier generations. Infrared and ultraviolet analysis, computer image processing, fractal analysis, metrological analysis using image analysis methods are modern methods useful especially in neuroanatomical research.
Starting in 1983, the Texas Group mass-produced MDMA in a Texas lab or imported it from California and marketed tablets using pyramid sales structures and toll-free numbers. MDMA could be purchased via credit card and taxes were paid on sales. Under the brand name "Sassyfras", MDMA tablets were sold in brown bottles. The Texas Group advertised "Ecstasy parties" at bars and discos, describing MDMA as a "fun drug" and "good to dance to". MDMA was openly distributed in Austin and Dallas–Fort Worth area bars and nightclubs, becoming popular with yuppies, college students, and gays. Recreational use also increased after several cocaine dealers switched to distributing MDMA following experiences with the drug. A California laboratory that analyzed confidentially submitted drug samples first detected MDMA in 1975. Over the following years the number of MDMA samples increased, eventually exceeding the number of MDA samples in the early 1980s. By the mid-1980s, MDMA use had spread to colleges around the United States.
Sources: en.wikipedia.org
Asian citrus psyllid on the UF / IFAS Featured Creatures Web site Species Profile – Citrus Greening and Species Profile – Asian Citrus Psyllid, National Invasive Species Information Center, National Agricultural Library. Lists general information and resources for citrus greening and the Asian citrus psyllid. CISR: Huanglongbing/Citrus Greening Center for Invasive Species Research page on Huanglongbing and Citrus Greening
=== Siriometer === The siriometer is an obsolete astronomical measure equal to one million astronomical units, i.e., one million times the average distance between the Sun and Earth. This distance is equal to about 15.8 light-years, 149.6 Pm, or 4.8 parsecs, and is about twice the distance from Earth to the star Sirius.
== Episode 6: Deja Vu == Matt Lee is a 20-year-old college student who suffers from fainting spells that only occur when he has a sense of Deja Vu, these fainting spells at times can cause his heart to stop all together. Matt states that when he was around 19, one day he just started feeling very light headed and had a sense of Deja Vu then shortly after he blacked out. When he woke back up and realized he had blacked out, he immediately went to the hospital, the next time he fainted had flatlined. Specifically his symptoms include a sense of tingling in his head that is followed by light-headedness, nausea, heart palpitations, loss of control, and then finally the Deja Vu before he faints. Matt is extremely afraid that these random fainting episodes could happen at any time during the day and he might not have someone to help him out, because of these he stays at home as much as he could. He expresses his disappointment in not being able to follow his goals in wanting to study computer science and wanting to find a cure or treatment that would allow him to be “free” again. Matt was admitted into Johns Hopkins Hospital for in depth testing of all his symptoms, the only definitive diagnosis known is the fact that Matt is experiencing Syncope. Syncope are essentially fainting spells that are caused by a decrease of blood reaching the brain, the only question is what is causing the decreased blood flow along with the other symptoms.
The reinforced labour faction of the party initially accorded a more left-wing orientation and facilitated the cooperation with the social democrats. Typically, the Zentrum defended anti-capitalist policies and promoted social policy, but never agreed with social democrats on the right to private property. By the late Twenties, however, the Center Party gradually returned to more conservative policies.
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。
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.