The short version of Melanocortin receptor fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-04-17. Anything still debated is marked as such rather than presented as settled.
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。
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.
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.
Tianeptine/naloxone reached phase 2 clinical trials for major depressive disorder and phase 1 clinical trials for post-traumatic stress disorders and cognition dysfunction related to corticosteroid use prior to the discontinuation of its development. Its development was discontinued for all indications in October 2023 due to lack of effectiveness for major depressive disorder in a phase 2 clinical trial.
In September 2022, the WHO updated their guidelines to recommend use of remdesivir for both non-hospitalized and hospitalized patients. This was based on final results from the SOLIDARITY trial that showed a reduction in mortality or progression to mechanical ventilation for non-ventilated patients.
Quotations related to Antimicrobial resistance at Wikiquote WHO fact sheet on antimicrobial resistance Animation of Antibiotic Resistance Archived 28 September 2022 at the Wayback Machine Bracing for Superbugs: Strengthening environmental action in the One Health response to antimicrobial resistance UNEP, 2023. CDC Guideline "Management of Multidrug-Resistant Organisms in Healthcare Settings, 2006"
Sources: en.wikipedia.org
As examples, Moderna's RNA vaccine candidate requires cold chain management just above freezing temperatures between 2 and 8 °C (36 and 46 °F) with limited storage duration (30 days), but the Pfizer-BioNTech RNA candidate requires storage between −80 and −60 °C (−112 and −76 °F), or colder throughout deployment until vaccination. In February 2021, Pfizer and BioNTech asked the U.S. Food and Drug Administration (FDA) to update the emergency use authorization (EUA) to permit the vaccine to be stored at between −25 and −15 °C (−13 and 5 °F) for up to two weeks before use. As of May 2021, Walvax is conducting Phase III trials for its mRNA vaccine which could be stored at room temperature for six months. After a vaccine vial is punctured to administer a dose, it is viable for only six hours, then must be discarded, requiring attention to local management of cold storage and vaccination processes. Because the COVID‑19 vaccine will likely be in short supply for many locations during early deployment, vaccination staff will have to avoid spoilage and waste, which typically are as much as 30% of the supply. The cold chain is further challenged by the type of local transportation for the vaccines in rural communities, such as by motorcycle or delivery drone, need for booster doses, use of diluents, and access to vulnerable populations, such as healthcare staff, children and the elderly.
Woodworking When wood is used as a construction material, whether as a structural support in a building or in woodworking objects, it will absorb or expel moisture until it is in equilibrium with its surroundings. Equilibration (usually drying) causes unequal shrinkage in the wood, and can cause damage to the wood if equilibration occurs too rapidly. The equilibration must be controlled to prevent damage to the wood. Wood burning When wood is burned (firewood), it is best to dry it first. Damage from shrinkage is not a problem here, as it may be in the case of drying for woodworking purposes. Moisture affects the burning process, with unburnt hydrocarbons going up the chimney. If a 50% wet log is burnt at high temperature, with good heat extraction from the exhaust gas leading to a 100°C exhaust temperature, about 5% of the energy of the log is wasted through evaporating and heating the water vapour. With condensers, the efficiency can be further increased; but, for the normal stove, the key to burning wet wood is to burn it very hot, perhaps starting fire with dry wood.
Intending to wrest back the initiative, sever UNITA's logistics lifelines to South West Africa and Zaire, and forestall any future insurgent offensives, FAPLA launched Operation Saluting October in mid-1987. The impetus for Saluting October likely originated with the Soviet military mission, which pressed the idea of a major conventional thrust to destroy UNITA's southeastern front as early as 1983. It had received a new commander that year, Lieutenant General Pyotr Gusev, former deputy commander of the Carpathian Military District. In light of the war's length, its cost, the rising death toll, and looming cuts in the Soviet military expenditure which would limit future efforts to support FAPLA's war effort, Gusev wanted a decisive multi-divisional offensive to crush UNITA once and for all. Operation Saluting October was a two-pronged offensive aimed at retaking three major settlements from UNITA, Cangamba, Cassamba, and Mavinga. The FAPLA command staff intended the attack on Cangamba and Cassamba as a feint, hoping to draw UNITA forces there and away from Mavinga. Once Mavinga was in government hands, FAPLA could expel the remaining insurgents from Moxico Province and pave the way for a final assault on Savimbi's headquarters at Jamba. Between 4 and 9 Soviet advisers were to be attached on the battalion level, albeit with strict orders not to participate in the fighting and withdraw from the front as necessary to avoid contact with UNITA. They were accompanied by a small number of Cuban advisers and East German technical personnel serving in a variety of support roles.
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.