intranasal route raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-04-07 and is reviewed periodically as new material appears.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
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。
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。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide (ACTH fragment analog) | Not a steroid; does not belong to the melanocortin agonist drugs by marketing category |
| Molecular formula | C37H51N9O10S (commonly cited) | Reported values vary slightly with salt and counter-ion content |
| Appearance | White to off-white lyophilized powder | A single batch may appear as a loose cake or fluffy solid |
| Solubility | Freely soluble in water and aqueous buffer | Stock solutions are usually prepared in sterile water or saline |
| Typical storage | −20 °C or below, desiccated and protected from light | Seal opened vials promptly to limit moisture uptake |
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
== Energy release == The Q value is defined as the total energy released in a given nuclear decay. In beta decay, Q is therefore also the sum of the kinetic energies of the emitted beta particle, neutrino, and recoiling nucleus. (Because of the large mass of the nucleus compared to that of the beta particle and neutrino, the kinetic energy of the recoiling nucleus can generally be neglected.) Beta particles can therefore be emitted with any kinetic energy ranging from 0 to Q. A typical Q is around 1 MeV, but can range from a few keV to a few tens of MeV. Since the rest mass of the electron is 511 keV, the most energetic beta particles are ultrarelativistic, with speeds very close to the speed of light. In the case of 187Re, the maximum speed of the beta particle is only 9.8% of the speed of light. The following table gives some examples:
The Wisconsin School was distinct from the New Left; while members of each found themselves allied at times, New Left critiques tended to be a good deal more radical both in analysis and in proposed solutions. Following Williams, revisionists placed more responsibility for the breakdown of postwar peace on the United States, citing a range of their efforts to isolate and confront the Soviet Union well before the end of World War II. They argued that American policymakers shared an overarching concern with maintaining the market system and capitalist democracy. To achieve that objective, they pursued an "open door" policy abroad, aimed at increasing access to foreign markets for American business and agriculture. Revisionist scholars challenged the widely accepted scholarly research that Soviet leaders were committed to postwar expansion of communism. They cited evidence that the Soviet Union's occupation of Eastern Europe had a defensive rationale and that Soviet leaders saw themselves as attempting to avoid encirclement by the United States and its allies. In that view, the Soviet Union was so weak and devastated after the end of World War II to be unable to pose any serious threat to the United States, who maintained a nuclear monopoly until the Soviet Union tested its first atomic bomb in August 1949. Revisionist historians have also presented the view that the origins of the Cold War date to the Allied intervention in the Russian Civil War.
Sumatriptan is structurally similar to the neurotransmitter serotonin (5-HT) and acts as an agonist of the serotonin 5-HT1B, 5-HT1D, and 5-HT1F receptors. Sumatriptan's primary therapeutic effect is related in its inhibition of the release of calcitonin gene-related peptide (CGRP), likely through its 5-HT1D/1B receptor agonist action. This has been substantiated by the efficacy of more recently developed CGRP targeting drugs and antibodies developed for the preventive treatment of migraine. How agonism of the 5-HT1D/1B receptors inhibits CGRP release is not fully understood. CGRP is believed to cause sensitization of trigeminal nociceptive neurons, contributing to the pain experienced in migraine. Sumatriptan is also shown to decrease the activity of the trigeminal nerve, which presumably accounts for sumatriptan's efficacy in treating cluster headaches. The injectable form of the drug has been shown to abort a cluster headache within 30 minutes in 77% of cases. Sumatriptan does not affect oxytocin or vasopressin levels in humans.
Physicists in the 1920s believed that the atomic nucleus contained protons plus a number of "nuclear electrons" that reduced the overall charge. These "nuclear electrons" were distinct from the electrons that orbited the nucleus. This incorrect hypothesis would have explained why the atomic numbers of the elements were less than their atomic weights, and why radioactive elements emit electrons (beta radiation) in the process of nuclear decay. Rutherford even hypothesized that a proton and an electron could bind tightly together into a "neutral doublet". Rutherford wrote that the existence of such "neutral doublets" moving freely through space would provide a more plausible explanation for how the heavier elements could have formed in the genesis of the Universe, given that it is hard for a lone proton to fuse with a large atomic nucleus because of the repulsive electric field. In 1928, Walter Bothe observed that beryllium emitted a highly penetrating, electrically neutral radiation when bombarded with alpha particles. It was later discovered that this radiation could knock hydrogen atoms out of paraffin wax. Initially it was thought to be high-energy gamma radiation, since gamma radiation had a similar effect on electrons in metals, but James Chadwick found that the ionization effect was too strong for it to be due to electromagnetic radiation, so long as energy and momentum were conserved in the interaction.
A nonstop mutation, also called a stop-loss variant, is a point mutation that occurs within a stop codon. Nonstop mutations cause the continued translation of an mRNA strand into what should be an untranslated region. Most polypeptides resulting from a gene with a nonstop mutation lose their function due to their extreme length and the impact on normal folding. Nonstop mutations differ from nonsense mutations in that they do not create a stop codon but, instead, delete one. Nonstop mutations also differ from missense mutations, which are point mutations where a single nucleotide is changed to cause replacement by a different amino acid. Nonstop mutations have been linked with many inherited diseases including endocrine disorders, eye disease, and neurodevelopmental disorders.
Sources: en.wikipedia.org
=== Thermal properties === Solid silver nitrate is robust and melts to give a dense (4.1 g/cm3), stable liquid above its 198 °C melting point. At temperatures around 250 °C it decomposes to release metallic silver and red-brown fumes of nitrogen dioxide. Full decomposition occurs at 440 °C.
== Synthesis == Pancreatic polypeptide is synthesised and secreted by PP cells (also known as gamma cells or F cells) of the pancreatic islets of the pancreas. These are found predominantly in the head of the pancreas.
=== Guatemala === The Mexican Army crackdown has driven some cartels to seek a safer location for their operations across the border in Guatemala, attracted by corruption, weak policing, and its position on the overland smuggling route. The smugglers pick up drugs from small planes that land at private airstrips hidden in the Guatemalan jungle. The cargo is then moved up through Mexico to the U.S. border. Guatemala has also arrested dozens of drug suspects and torched huge cannabis and poppy fields. The U.S. government sent speedboats and night-vision goggles under a regional drug aid package. Los Zetas have gained ground in Guatemala after they killed several high-profile members and the supreme leader of Los Leones, an organized crime group from Guatemala. In February 2009, Los Zetas threatened to kill the president of Guatemala, Álvaro Colom. On March 1, 2010, Guatemala's chief of national police and the country's top anti-drugs official were arrested over alleged links to drug trafficking. A report from the Brookings Institution warns that, without proactive, timely efforts, the violence will spread throughout the Central American region. In August 2025, Guatemala granted temporary humanitarian status to 161 Mexicans fleeing cartel violence in Chiapas.
=== Cardiac === ANP inhibits cardiac hypertrophy in heart failure as well as fibrosis. Fibrosis is inhibited by preventing fibroblasts from entering heart tissue and replicating, as well as decreasing inflammation. ANP prevents hypertrophy by inhibiting calcium influx that is caused by norepinephrine. Re-expression of NPRA rescues the phenotype.
Sources: en.wikipedia.org
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.
It was developed in the Soviet Union during the early 1980s by groups at the Institute of Molecular Genetics in Moscow. Russian approval for intranasal use followed, and it has been marketed there since. Western laboratories encountered it mainly through translated literature and, later, through online research-chemical trade.
It holds a Russian registration as a prescription nasal product but has no approval from the European Medicines Agency or the United States Food and Drug Administration. Buyers outside Russia usually receive material sold strictly for laboratory research. That distinction matters because research-grade and pharmaceutical-grade products carry different documentation and testing expectations.
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。