This is a working overview of MC4 receptor, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-27 and is reviewed periodically as new material appears.
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。
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.
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.
The king cobra has an eminent position in the mythology and folklore of India, Bangladesh, Sri Lanka and Myanmar. A ritual in Myanmar involves a king cobra and a female snake charmer. The charmer is a priestess who is usually tattooed with three pictograms and kisses the snake on the top of its head at the end of the ritual. Members of the Pakokku clan tattoo themselves with ink mixed with cobra venom on their upper bodies in a weekly inoculation that they believe would protect them from the snake, though no scientific evidence supports this. It is regarded as the national reptile of India. In India, the king cobra is believed to possess exceptional memory; according to a myth, the killer of a king cobra stays in the eyes of the snake as an image, which is later picked up by the snake's partner and used to hunt down the killer for revenge. Because of this myth, whenever a cobra is killed, especially in India, the head, if not the entire body, is either crushed or burned to destroy the eyes completely. In Bangkok's Bang Khun Thian district is a shrine to the king cobra by Rama II Road that was built after the nest and young of a large female king cobra were destroyed during the construction of the road. The original shrine is dedicated to a female spirit associated with the cobra. Nearby stands another shrine dedicated to a male spirit, believed to be the mate of the female king cobra; according to local belief, he later came there to meditate and perform ascetic practices in dedication to the female cobra and her offspring after their deaths.
Initially, this development was not regarded by the medical profession as a clinically meaningful development. However, by 1996, the advent of insulin analogues which had vastly improved absorption, distribution, metabolism, and excretion (ADME) characteristics which were clinically meaningful based on this early biotechnology development. In 2005, a new drug to treat type 2 diabetes, derived from the Gila monster, was approved by the Food and Drug Administration. The venom of the lizard contains exendin 4, which triggers one of the insulin-releasing pathways.
Electrical charges have been omitted for simplicity of notation. The square brackets indicate concentration, and the subscripts to the stability constants, β, indicate the stoichiometry of the complex. When the analytical concentration of methylamine is twice that of ethylenediamine and the concentration of copper is the same in both reactions, the concentration [Cd(en)] is much higher than the concentration [Cd(MeNH2)2] because β11 ≫ β12. An equilibrium constant, K, is related to the standard Gibbs free energy,
Sources: en.wikipedia.org
induction phase, 5 mg per kilogram intravenously every 12 hours for 14–21 days, the intravenous dose given as a 1-hour infusion maintenance phase, 5 mg per kg intravenously every day Stable disease is treated with 1000 mg orally three times daily. Similar dosing is used to prevent disease in high-risk patients, such as those infected with human immunodeficiency virus (HIV) or those with organ transplants. Ganciclovir is also available in slow-release formulations for insertion into the vitreous humour of the eye, as treatment for CMV retinitis (associated with HIV infection). A topical ophthalmic gel preparation of Ganciclovir was approved for the treatment of acute herpes simplex keratitis.
Additionally, it reacts with NADPH-dependent acetoacetyl-coenzyme A reductase, also known as PhaB, in a pathway that produces polyester polyhydroxyalkanoate (PHA). The reduction of acetoacetyl-coA by Pha creates (R)-3-hydroxybutyryl-CoA, which polymerizes to PHA. The pathway is present in bacteria such as Ralstonia eutropha and the PCC6803 strain of Synechocystis. Mover over, Acetoacetyl-CoA is involved with neuronal development involving lipogenesis and providing fats and cholesterol for neuronal cells.
1993/2257) Bath Mental Health Care National Health Service Trust (Transfer of Trust Property) Order 1993 (S.I. 1993/2258) Wiltshire Health Care National Health Service Trust (Transfer of Trust Property) Order 1993 (S.I. 1993/2259) North Mersey Community National Health Service Trust (Transfer of Trust Property) Order 1993 (S.I. 1993/2260) Bath and West Community National Health Service Trust (Transfer of Trust Property) Order 1993 (S.I. 1993/2261) Royal United Hospital, Bath, National Health Service Trust (Transfer of Trust Property) Order 1993 (S.I. 1993/2262) Weybourne Community National Health Service Trust (Transfer of Trust Property) Order 1993 (S.I. 1993/2263) King's Lynn and Wisbech Hospitals National Health Service Trust (Transfer of Trust Property) Order 1993 (S.I. 1993/2264) Hydrocarbon Oil (Amendment) Regulations 1993 (S.I. 1993/2267) Local Government Act 1988 (Defined Activities) (Exemption) (Horsham District Council and Worthing Borough Council) Order 1993 (S.I. 1993/2269) Finance (No. 2) Act 1992 (Commencement No. 6 and Transitional Provisions and Savings) Order 1993 (S.I. 1993/2272) Income Tax (Employments) (Amendment) Regulations 1993 (S.I. 1993/2276) Smoke Control Areas (Exempted Fireplaces) Order 1993 (S.I. 1993/2277) Sea Fish Licensing (Variation) (No. 2) Order 1993 (S.I. 1993/2291) Friendly Societies (Proxy Voting) Regulations 1993 (S.I. 1993/2294) Commissioners for Oaths (Fees) Order 1993 (S.I. 1993/2297) Commissioners for Oaths (Authorised Persons) (Fees) Order 1993 (S.I.
Sources: en.wikipedia.org
The lack of HAND1 detection in the developing embryo leads to many of the structural defects that causes heart disease and facial deformities while the dosage of HAND1 relates to the severity of these maladies. HAND factors function in the formation of the right ventricle, left ventricle, aortic arch arteries, epicardium, and endocardium implicating them as mediators of congenital heart disease. In addition, HAND1 is uniquely expressed in trophoblasts and is essential for early trophoblast differentiation.
Drug Information Association (DIA) EVENT: DIA/FDA Orphan Drug Designation Workshop November 2010 Archived 2010-10-28 at the Wayback Machine European Commission - The Orphan drugs strategy List of European Orphan Drugs USA Food and Drug Administration: The Orphan Drug Act (as amended) US FDA List of Orphan Designations and Approvals
into the general solution produces orbits that escape to infinity (while still satisfying the equation of motion). Substituting the definitions for the axial and cyclotron frequencies, one might also write this condition as
=== Pharmacodynamics === Dihydroergotamine's antimigraine activity is due to its action as an agonist at the serotonin 5-HT1B, 5-HT1D, and 5-HT1F receptors. It also interacts with other serotonin, adrenergic, and dopamine receptors. Dihydroergotamine is an agonist of the serotonin 5-HT2B receptor and has been associated with cardiac valvulopathy. In spite of acting as an agonist of the serotonin 5-HT2A receptor, dihydroergotamine has been described as non-hallucinogenic. This is also the case with certain other ergoline derivatives, such as bromocriptine and pergolide.
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.