Melanocortin receptor is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-11-30. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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。
| Property | Value | Notes |
|---|---|---|
| Appearance | White lyophilized powder | Typical for synthetic peptides |
| Solubility | Freely soluble in water | Also soluble in saline |
| Storage temperature | -20 C or below | Protect from repeated freeze-thaw |
| Analytical method | Reverse-phase HPLC | Confirms purity and identity |
| Common synonym | ACTH(4-10) analog | Reflects structural origin |
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
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.
Protein inhibition by inhibitor binding may induce obstruction in pathway regulation, homeostatic regulation and physiological function. Competitive inhibitors compete with substrate to bind to free enzymes at active sites and thus impede the production of the enzyme-substrate complex upon binding. For example, carbon monoxide poisoning is caused by the competitive binding of carbon monoxide as opposed to oxygen in hemoglobin. Uncompetitive inhibitors, alternatively, bind concurrently with substrate at active sites. Upon binding to an enzyme substrate (ES) complex, an enzyme substrate inhibitor (ESI) complex is formed. Similar to competitive inhibitors, the rate at product formation is decreased also. Lastly, mixed inhibitors are able to bind to both the free enzyme and the enzyme-substrate complex. However, in contrast to competitive and uncompetitive inhibitors, mixed inhibitors bind to the allosteric site. Allosteric binding induces conformational changes that may increase the protein's affinity for substrate. This phenomenon is called positive modulation. Conversely, allosteric binding that decreases the protein's affinity for substrate is negative modulation.
=== Physical properties === Californium is a silvery-white actinide metal with a melting point of 900 ± 30 °C (1,650 ± 50 °F) and an estimated boiling point of 1,743 K (1,470 °C; 2,680 °F). The pure metal is malleable and is easily cut with a knife. Californium metal starts to vaporize above 300 °C (570 °F) when exposed to a vacuum. Below 51 K (−222 °C; −368 °F) californium metal is either ferromagnetic or ferrimagnetic (it acts like a magnet), between 48 and 66 K it is antiferromagnetic (an intermediate state), and above 160 K (−113 °C; −172 °F) it is paramagnetic (external magnetic fields can make it magnetic). It forms alloys with lanthanide metals but little is known about the resulting materials. The element has two crystalline forms at standard atmospheric pressure: a double-hexagonal close-packed form dubbed alpha (α) and a face-centered cubic form designated beta (β). The α form exists below 600–800 °C with a density of 15.10 g/cm3 and the β form exists above 600–800 °C with a density of 8.74 g/cm3. At 48 GPa of pressure the β form changes into an orthorhombic crystal system due to delocalization of the atom's 5f electrons, which frees them to bond. The bulk modulus of a material is a measure of its resistance to uniform pressure. Californium's bulk modulus is 50±5 GPa, which is similar to trivalent lanthanide metals but smaller than more familiar metals, such as aluminium (70 GPa).
== Clinical implications == The MEN1 phenotype is inherited via an autosomal-dominant pattern and is associated with neoplasms of the pituitary gland, the parathyroid gland, and the pancreas (the 3 "P"s). While these neoplasias are often benign (in contrast to tumours occurring in MEN2A), they are adenomas and, therefore, produce endocrine phenotypes. Pancreatic presentations of the MEN1 phenotype may manifest as Zollinger–Ellison syndrome. MEN1 pituitary tumours are adenomas of anterior cells, typically prolactinomas or growth hormone-secreting. Pancreatic tumours involve the islet cells, giving rise to gastrinomas or insulinomas. In rare cases, adrenal cortex tumours are also seen.
The plant was ordered to be planted with great religious care at what is now known as the villa surbana, where it grew into a grove. According to Jane Clark Reeder, when Julio-Claudians had military success they would take a laurel branch from the villa.
Sources: en.wikipedia.org
=== Mice === Mouse FPR receptors localize to chromosome 17A3.2 in the following order: Fpr1, Fpr-rs2 (or fpr2), Fpr-rs1 (or LXA4R), Fpr-rs4, Fpr-rs7, Fpr-rs7, Fpr-rs6, and Fpr-rs3; Pseudogenes ψFpr-rs2 and ψFpr-rs3 (or ψFpr-rs5) lie just after Fpr-rs2 and Fpr-rs1, respectively. All of the active mouse FPR receptors have ≥50% amino acid sequence identity with each other as well as with the three human FPR receptors. Based on its predominantly intracellular distribution, mFpr-rs1 correlates, and therefore may share functionality, with human FPR3; However, the large number of mouse compared to human FPR receptors makes it difficult to extrapolate human FPR functions based on genetic (e.g. gene knockout or forced overexpression) or other experimental manipulations of the FPR receptors in mice.
Bones are surrounded by a membrane known as the periosteum (Greek περῐ́ (perí), around; Greek ὀστέον (ostéon), bone), and comprise multiple layers, depending on the type of bone, including yellow and red bone marrow, spongy bone, and the endosteum. There are five general classifications of bones: Long bones are characterized by a shaft known as the diaphysis, which is much longer than its width, and an epiphysis (Greek ἐπι- (epi-) upon, outside, over), a rounded head at each end of the shaft, connected to the diaphysis by the epiphyseal plate. They are made up mostly of compact bone, with lesser amounts of marrow, located within the medullary cavity, and areas of spongy, cancellous bone at the ends of the bones. Short bones are roughly cube-shaped, and have only a thin layer of compact bone surrounding a spongy interior. Short bones provide stability and support as well as some limited motion. Flat bones are thin and generally curved, with two parallel layers of compact bone sandwiching a layer of spongy bone. Sesamoid bones are bones embedded in tendons. Since they act to hold the tendon further away from the joint, the angle of the tendon is increased and thus the leverage of the muscle is increased. Irregular bones do not fit into the above categories. They consist of thin layers of compact bone surrounding a spongy interior. As implied by the name, their shapes are irregular and complicated. Often this irregular shape is due to their many centers of ossification or because they contain bony sinuses.
=== Size and other body parts === There is no correlation between shoe size and stretched penis size. Nose size was highly related to stretched penile length in Japanese male cadavers. There may be a link between the malformation of the genitalia and the human limbs. The development of the penis in an embryo is controlled by some of the same Hox genes (in particular HOXA13 and HOXD13) as those that control the development of the limbs. Mutations of some Hox genes that control the growth of limbs cause malformed genitalia (hand–foot–genital syndrome).
Sources: en.wikipedia.org
Acid proteases Neutral proteases involved in type 1 hypersensitivity. Here, it is released by mast cells and causes activation of complement and kinins. This group includes the calpains. Basic proteases (or alkaline proteases)
==== Spanish colonial America ==== In Jamaica and elsewhere in the Caribbean area, the Spanish enslaved many of the Taino natives. Some of them escaped, and some hurled themselves and their children off of cliffs to avoid enslavement, but most died from European diseases and overwork. The practice began under Christopher Columbus, who was looking for gold to finance his future expeditions, and was continued by the other conquistadors who followed in his wake. In 1519, Hernán Cortés brought the first modern slave to Mexico. In the mid-16th century, the Spanish New Laws, prohibited slavery of the indigenous people, including the Aztecs. A labour shortage resulted. This led to the African slaves being imported, as they were not susceptible to smallpox. In exchange, many Africans were afforded the opportunity to buy their freedom, while eventually others were granted their freedom by their masters. Spain practically did not trade in slaves until 1810 after the rebellions and independence of its American territories or viceroyalties. After the Napoleonic invasions, Spain had lost its industry and its American territories, except in Cuba and Puerto Rico, where the African slave trade to Cuba began on a massive scale from 1810 onwards. It was started by French planters exiled from the French lost colony Saint Domingue (Haiti) who settled in the eastern part of Cuba. In 1789, the Spanish Crown led an effort to reform slavery, as the demand for slave labour in Cuba was growing.
Artificial bone can be created from ceramics such as calcium phosphates (e.g. hydroxyapatite and tricalcium phosphate), Bioglass and calcium sulfate; all of which are biologically active to different degrees depending on solubility in the physiological environment. These materials can be doped with growth factors, ions such as strontium or mixed with bone marrow aspirate to increase biological activity. Some authors believe this method is inferior to autogenous bone grafting; however, infection and rejection of the graft is much less of a risk, and the mechanical properties such as Young's modulus are comparable to bone. The presence of elements such as strontium can result in higher bone mineral density and enhanced osteoblast proliferation in vivo.
However, others have pointed out that C-peptides are produced in hypoglycaemic attacks caused by insulin produced naturally in the body, and these were not detected in any of the blood tests of the victims, indicating that the insulin had been introduced to their bodies externally and artificially. Norris lost an appeal against his conviction in 2009. In February 2021, the Criminal Cases Review Commission referred the case back to the Court of Appeal; this second appeal, heard in 2025, was also unsuccessful. Norris is believed to have been inspired by Jessie McTavish, a fellow Scottish nurse who was convicted of murdering a patient with insulin in 1974 before having her conviction quashed in 1975. The incident had happened at Ruchill Hospital in Glasgow, less than a mile from where Norris grew up. Shortly before he registered as a nurse, he had learned about McTavish.
Sources: en.wikipedia.org
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.
Peptidases degrade the compound within minutes in circulation. This short half-life is one reason nasal delivery is used, placing the substance close to the olfactory and trigeminal pathways.
No large multicenter trials have been published in English-language journals. The existing human evidence consists mainly of smaller studies conducted in Russia, which limits generalization.
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。