This is a working overview of Melanocortin receptor, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-03-25 and is reviewed periodically as new material appears.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
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.
Solid material is normally kept at minus 20 degrees Celsius in a sealed, desiccated container. Reconstituted solutions are less stable and are usually divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of activity. Light exposure is minimized by using amber glassware or foil wrapping. Published stability data for this peptide are sparse, so recommended storage conditions rest mainly on general practice for short synthetic peptides rather than on dedicated study.
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
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.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
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.
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.
== Copolymer == Depending on the ratio of lactide to glycolide used for the polymerization, different forms of PLGA can be obtained: these are usually identified in regard to the molar ratio of the monomers used (e.g. PLGA 75:25 identifies a copolymer whose composition is 75% lactic acid and 25% glycolic acid). The crystallinity of PLGAs will vary from fully amorphous to fully crystalline depending on block structure and molar ratio. PLGA typically show a glass transition temperature in the range of 40-60 °C. PLGA can be dissolved by a wide range of solvents, depending on composition. Higher lactide polymers can be dissolved using chlorinated solvents whereas higher glycolide materials will require the use of fluorinated solvents such as HFIP. PLGA undergoes hydrolysis in the body to produce the original monomers: lactic acid and glycolic acid. These two monomers under normal physiological conditions, are by-products of various metabolic pathways in the body. Lactic acid is metabolized in the tricarboxylic acid cycle and eliminated via carbon dioxide and water. Glycolic acid is metabolized in the same way, and also excreted through the kidney. The body also can metabolize the two monomers, which in the case of glycolic acid produces small amounts of the toxic oxalic acid, though the amounts produced from typical applications are minuscule and there is minimal systemic toxicity associated with using PLGA for biomaterial applications.
Since the location of the beams is relatively easy to determine, the precision of the measurement depends primarily on how small the setup can be made. If the beams are too far apart, the flow could change substantially between them, thus the measurement becomes an average over that space. Moreover, multiple particles could reside between them at any given time, and this would corrupt the signal since the particles are indistinguishable. For such a sensor to provide valid data, it must be small relative to the scale of the flow and the seeding density. MOEMS approaches yield extremely small packages, making such sensors applicable in a variety of situations.
=== Pharmacokinetics === Metabolism of myristicin yields 3-methoxycatechol and enzymatically forms 5-allyl-1-methoxy-2,3-dihydroxybenzene (oxidation of the methylenedioxy group). Myristicin is also transformed into demethylenylmyristicin, dihydroxymyristicin, and elemicin is transformed into O-demethylelemicin, O-demethyldihydroxyelemicin, and safrole. There has been speculation that myristicin might be converted into the psychedelic MMDA, but this has not been demonstrated in humans. However, two nitrogen-containing metabolites of myristicin have been identified in the urine of rats and guinea pigs following oral or intraperitoneal administration. The major basic ninhydrin-positive urinary metabolite of myristicin in the rat is 3-piperidyl-1-(3′methoxy-4′,5′-methylenedioxyphenyl)-1-propanone, while the major basic ninhydrin-positive urinary metabolite of the guinea pig is 3-pyrrolidinyl-1-(3′methoxy-4′,5′-methylenedioxyphenyl)-1-propanone. Equivalent nitrogen-containing metabolites have also been identified for safrole and elemicin, including the dimethylamine, piperidine and pyrrolidine forms. Whether these aminated metabolites are involved in the reported psychoactive and hallucinogenic effects of botanical sources of these allylbenzenes like nutmeg is not known.
== Taxonomy == The maqui was first scientifically described by Juan Ignacio Molina in 1782, who named it Cornus chilensis. In 1914, Stephen Conrad Stuntz assigned it to the genus Aristotelia that had been erected by Charles Louis L'Héritier de Brutelle in 1786, and made the new combination A. chilensis.
2-Nonenal is an unsaturated aldehyde. The colorless liquid is an important aroma component of aged beer and buckwheat, and is insoluble in water. 2-Nonenal reacts with the Wittig reagent methylenetriphenylphosphorane to give hexyl-1,3-butadiene.
Sources: en.wikipedia.org
In 1872, Russian Alexander Lodygin invented an incandescent light bulb and obtained a Russian patent in 1874. He used as a burner two carbon rods of diminished section in a glass receiver, hermetically sealed, and filled with nitrogen, electrically arranged so that the current could be passed to the second carbon when the first had been consumed. Later he lived in the US, changed his name to Alexander de Lodyguine and applied for and obtained patents for incandescent lamps having chromium, iridium, rhodium, ruthenium, osmium, molybdenum and tungsten filaments. On 24 July 1874, a Canadian patent was filed by Henry Woodward and Mathew Evans for a lamp consisting of carbon rods mounted in a nitrogen-filled glass cylinder. They were unsuccessful at commercializing their lamp, and sold rights to their patent to Thomas Edison in 1879. (Edison needed ownership of the novel claim of lamps connected in a parallel circuit.) The government of Canada maintains that it is Woodward and Evans who invented the lightbulb.
=== Characterization === Carboxylic acids are readily identified as such by infrared spectroscopy. They exhibit a sharp band associated with vibration of the C=O carbonyl bond (νC=O) between 1680 and 1725 cm−1. A characteristic νO–H band appears as a broad peak in the 2500 to 3000 cm−1 region. By 1H NMR spectrometry, the hydroxyl hydrogen appears in the 10–13 ppm region, although it is often either broadened or not observed owing to exchange with traces of water.
=== Deputy Prime Minister: 1995–1997 === Heseltine had a two-hour meeting with Major on the morning of the leadership vote. He was promoted to Deputy Prime Minister and First Secretary of State. He was given a swipe card to enter 10 Downing Street whenever he liked and the right to attend any committee he wished. He chaired four Cabinet Committees, including Environment and Local Government, and two new committees: Competitiveness Committee (effectively, industrial strategy) and the Coordination and Presentation of Government Policy (EDCP) which met every weekday at 8.30am. The matter of a referendum on joining the euro, after much press speculation, was raised again at Cabinet by Douglas Hogg in the spring of 1996, very likely (in Clarke's view) with Major's approval; Clarke records that Heseltine spoke "with passionate intensity" at Cabinet against a referendum, believing both that referendums were pernicious and that no concession would be enough to please the Eurosceptics. Clarke, who had already threatened resignation over the issue, also opposed the measure and, although Clarke and Heseltine were in a small minority, Major once again deferred a decision. Major, Heseltine and Clarke eventually reached agreement in April 1996, in what Clarke describes as "a tense meeting … rather like a treaty session", that there would be a commitment to a referendum before joining the euro, but that the pledge would be valid for one Parliament only (i.e.
absolute pressures used in order to ventilate non-compliant lungs. shearing forces, particularly associated with rapid changes in gas velocity. The resultant alveolar rupture can lead to pneumothorax, pulmonary interstitial emphysema (PIE) and pneumomediastinum. Barotrauma is a recognised complication of mechanical ventilation that can occur in any patient receiving mechanical ventilation, but is most commonly associated with acute respiratory distress syndrome. It used to be the most common complication of mechanical ventilation but can usually be avoided by limiting tidal volume and plateau pressure to less than 30 to 50 cm water column (30 to 50 mb). As an indicator of transalveolar pressure, which predicts alveolar distention, plateau pressure or peak airway pressure (PAP) may be the most effective predictor of risk, but there is no generally accepted safe pressure at which there is no risk. Risk also appears to be increased by aspiration of stomach contents and pre-existing disease such as necrotising pneumonia and chronic lung disease. Status asthmaticus is a particular problem as it requires relatively high pressures to overcome bronchial obstruction. When lung tissues are damaged by alveolar over-distension, the injury may be termed volutrauma, but volume and transpulmonary pressure are closely related. Ventilator induced lung injury is often associated with high tidal volumes (Vt). Other injuries with similar causes are decompression sickness and ebullism.
Sources: en.wikipedia.org
Valve was founded in Kirkland, Washington in 1996 by the former Microsoft employees Gabe Newell and Mike Harrington. For their first product, Valve settled on a concept for a horror first-person shooter (FPS) game. They did not want to build their own game engine, as this would have created too much work for a small team and Newell planned to innovate in different areas. Instead, Valve licensed the Quake engine and the Quake II engine from id Software and combined them with their own code. Newell estimated that around 75% of the final engine code was by Valve. As the project expanded, Valve cancelled development of a fantasy role-playing game, Prospero, and the Prospero team joined the Half-Life project. Half-Life was inspired by the FPS games Doom (1993) and Quake (1996), Stephen King's 1980 novella The Mist, and a 1963 episode of The Outer Limits titled "The Borderland". According to the designer Harry Teasley, Doom was a major influence and the team wanted Half-Life to "scare you like Doom did". The project had the working title Quiver, after the Arrowhead military base from The Mist. The name Half-Life was chosen because it was evocative of the theme, not clichéd, and had a corresponding visual symbol: the Greek letter λ (lower-case lambda), which represents the decay constant in the half-life equation. According to the designer Brett Johnson, the level design was inspired by environments in the manga series Akira.
Pre-existing acute or chronic liver dysfunction or family history of severe liver inflammation (hepatitis), particularly medicine related. Pregnancy 11% risk of birth defects and 30-40% risk of neuro-developmental disabilities which can be permanent Known hypersensitivity to valproate or any of the ingredients used in the preparation Urea cycle disorders Hepatic porphyria Hepatotoxicity Mitochondrial disease Pancreatitis Porphyria
Postprandial somnolence (colloquially known as food coma or after-meal dip) is a benign state of drowsiness or lassitude following a meal, a general state of sleepiness and low energy related to activation of the parasympathetic nervous system in response to mass in the gastrointestinal tract. While there are numerous theories surrounding this behavior, such as decreased blood flow to the brain, neurohormonal modulation of sleep through digestive coupled signaling, or vagal stimulation, very few have been explicitly tested. To date, human studies have loosely examined the behavioral characteristics of postprandial sleep, demonstrating potential shifts in EEG spectra and self-reported sleepiness. To date, the only clear animal models for examining the genetic and neuronal basis for this behavior are the fruit fly, the mouse, and the nematode Caenorhabditis elegans.
Ferric chloride test (detects abnormal metabolites in urine) Ninhydrin paper chromatography (detects abnormal amino acid patterns) Guthrie test (detects excessive amounts of specific amino acids in blood) The dried blood spot can be used for multianalyte testing using Tandem Mass Spectrometry (MS/MS). This given an indication for a disorder. The same has to be further confirmed by enzyme assays, IEX-Ninhydrin, GC/MS or DNA Testing. Quantitative measurement of amino acids in plasma and urine IEX-Ninhydrin post-column derivitization liquid ion chromatography (detects abnormal amino acid patterns and quantitative analysis) Urine organic acid analysis by gas chromatography–mass spectrometry Plasma acylcarnitine analysis by mass spectrometry Urine purine and pyrimidine analysis by gas chromatography-mass spectrometry Specific diagnostic tests (or focused screening for a small set of disorders):
However, despite having on-average 25(OH)D serum concentrations below the 50 nmol/L amount considered sufficient, African Americans have higher bone mineral density and lower fracture risk when compared to European-origin people. Possible mechanisms may include higher calcium retention, lower calcium excretion, and greater bone resistance to parathyroid hormone, also genetically lower serum vitamin D-binding protein which would result in adequate bioavailable 25(OH)D despite total serum 25(OH)D being lower. The bone density and fracture risk paradox does not necessarily carry over to non-skeletal health conditions, such as arterial calcification, cancer, diabetes or all-cause mortality. People with dark complexions may need different definitions for vitamin D deficiency, insufficiency, and adequate.
Sources: en.wikipedia.org
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
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.