Everything below concerns Melanocortin receptor. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-08-05. Where a claim depends on a specific study, the study is described rather than over-claimed.
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。
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。
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
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。
| 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.
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.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
== History & etymology == It had been known to physiologists for over a century that a vasoconstrictor material appears in serum when blood was allowed to clot. In 1935, Italian Vittorio Erspamer, working in Pavia, showed an extract from enterochromaffin cells made intestines contract. Some believed it contained adrenaline, but two years later, Erspamer was able to show it was a previously unknown amine, which he named "enteramine". In 1948, Maurice M. Rapport, Arda Green, and Irvine Page of the Cleveland Clinic discovered a vasoconstrictor substance in blood serum, and since it was a serum agent affecting vascular tone, they named it serotonin. In 1952, enteramine was shown to be the same substance as serotonin, and as the broad range of physiological roles was elucidated, the abbreviation 5-HT of the proper chemical name 5-hydroxytryptamine became the preferred name in the pharmacological field. Synonyms of serotonin include: 5-hydroxytriptamine, enteramine, substance DS, and 3-(β-aminoethyl)-5-hydroxyindole. In 1953, Betty Twarog and Page discovered serotonin in the central nervous system. Page regarded Erspamer's work on Octopus vulgaris, Discoglossus pictus, Hexaplex trunculus, Bolinus brandaris, Sepia, Mytilus, and Ostrea as valid and fundamental to understanding this newly identified substance, but regarded his earlier results in various models – especially those from rat blood – to be too confounded by the presence of other bioactive chemicals, including some other vasoactives.
=== Causes === The most common cause of periwound issues is excessive moisture present in the area surrounding the wound. Exudate from heavily draining wounds causes irritation of the periwound that may lead to maceration, excoriation, and otherwise compromise skin integrity. This type of damage is more common in chronic wounds due to exudate composition which differs from fluids produced in acute wounds or burns. Chronic wound exudate contains proteolytic enzymes and other components that degrade skin integrity and predispose it to inflammation. Moisture-associated skin damage can also be caused by bodily fluids or other contaminants that enter the periwound areas, for example, in patients with urinary or fecal incontinence, or colostomy patients. Other causes include dryness of the skin due to ageing and skin or systemic disorders, allergic reactions to wound care products, damage that may result from poor application and removal technique of adhesive products used in wound treatment, as well as exposure to infection or extrinsic contaminants at the time of wound dressing changes.
== Historical uses == Especially in medieval times, the end of a chain could be attached to a chain tower or boom tower. This allowed safe raising or lowering of the chain, as they were often heavily fortified. By raising or lowering a chain or boom, access could be selectively granted rather than simply rendering the stretch of water completely inaccessible. The raising and lowering could be accomplished by a windlass mechanism or a capstan. Booms or chains could be broken by a sufficiently large or heavy ship, and this occurred on many occasions, including the siege of Damietta, the raid on the Medway and the Battle of Vigo Bay.A Frequently, however, attackers instead seized the defences and cut the chain or boom by more conventional methods. The boom at the siege of Derry, for example, was cut by sailors in a longboat. As a key portion of defences, booms were usually heavily defended. This involved shore-based chain towers, artillery batteries, or forts. In the Age of Sail, a boom protecting a harbour could have several ships defending it with their broadsides, discouraging assaults on the boom. On some occasions, multiple booms spanned a single stretch of water.
Sources: en.wikipedia.org
It has been suggested that suicidal behavior and ideation may be associated with use of GLP-1 receptor-agonist medication, but studies in several countries since 2024 do not support this. In January 2026, the US Food and Drug Administration requested removal of a suicidal behavior and ideation warning from GLP-1 receptor-agonist medications.
=== Pharmacodynamics === SR-17018 acts as a biased partial agonist of the μ-opioid receptor (MOR), with strong selectivity for activation of G protein signaling over β-arrestin2 recruitment. Its affinities (Ki) for the human opioid receptors have been reported to be 11 nM for the MOR, 68 nM for the κ-opioid receptor (KOR), and >10,000 nM for the δ-opioid receptor (DOR). In terms of MOR activation, the drug had activational potencies and efficacies (EC50Tooltip half-maximal effective concentration and EmaxTooltip maximal efficacy) of 97–193 nM (72–75%) for GTPγS binding, 76 nM (105%) for cAMPTooltip cyclic adenosine monophosphate accumulation, and >10,000 nM (10%) for β-arrestin2 recruitment. Both GTPγS binding and cAMP accumulation are measures of G protein signaling. The drug showed a calculated bias factor for GTPγS binding over β-arrestin2 recruitment of 80 to 100 relative to DAMGO. SR-17018 also showed strong bias for G protein activation over β-arrestin2 recruitment using mouse proteins, albeit with reduced efficacy for GTPγS binding (Emax = 37%). β-Arrestin2 activation may contribute to opioid tolerance, though it is not the only mechanism of tolerance to these drugs. SR-17018 shows a strikingly different MOR phosphorylation profile from other MOR biased, partial, and full agonists. Additional studies have characterized the interactions of SR-17018 with the MOR, including activational potencies and efficacies at downstream signaling pathways, as well.
== History == The efficacy of azacitidine to treat juvenile myelomonocytic leukemia was evaluated in AZA-JMML-001 (NCT02447666), an international, multicenter, open-label study to evaluate the pharmacokinetics, pharmacodynamics, safety, and activity of azacitidine prior to hematopoietic stem cell transplantation in 18 pediatric patients with juvenile myelomonocytic leukemia.
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。
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。