BDNF expression raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-01-20. Anything still debated is marked as such rather than presented as settled.
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.
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。
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。
| 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 |
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Later generations of the molecule include an N-acetylated form and an amidated form, both marketed online alongside the parent peptide. These variants differ in terminal chemistry and stability, and they are frequently discussed in the same breath even though they have not been compared in controlled trials. Supply outside formal healthcare systems comes largely from laboratories that synthesize peptides to order. Purity and identity of these materials vary widely, and no single body oversees the international trade.
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
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.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
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.
=== High Performance Liquid Chromatography === High Performance Liquid Chromatography (HPLC) in the field of microfluidics comes in two different forms. Early designs included running liquid through the HPLC column then transferring the eluted liquid to microfluidic chips and attaching HPLC columns to the microfluidic chip directly. The early methods had the advantage of easier detection from certain machines like those that measure fluorescence. HPLC columns have been integrated into microfluidic chips. The main advantage of integrating HPLC columns into microfluidic devices is the smaller form factor that can be achieved, which allows for additional features to be combined within one microfluidic chip. Integrated chips can also be fabricated from multiple different materials, including glass and polyimide which are quite different from the standard material of PDMS used in many different droplet-based microfluidic devices. This is an important feature because different applications of HPLC microfluidic chips may call for different pressures. PDMS fails in comparison for high-pressure uses compared to glass and polyimide. High versatility of HPLC integration ensures robustness by avoiding connections and fittings between the column and chip. The ability to build off said designs in the future allows the field of microfluidics to continue expanding its potential applications. The potential applications surrounding integrated HPLC columns within microfluidic devices have proven expansive over the last 10–15 years.
=== Supplementation === Patients are recommended to take folic acid and vitamin B12 supplement even if levels are normal when they are on pemetrexed therapy. (In clinical trials for mesothelioma, folic acid and B12 supplementation reduced the frequency of adverse events.) It is also recommended for patients to be on a glucocorticoid (e.g. dexamethasone) on the day prior, day of, and day after pemetrexed infusion to avoid skin rashes.
=== Hardware === The technology made by Dionex includes the Rapid Separation LC (RSLC) and polymeric HPLC columns, a type of monolithic HPLC column. Unlike the inorganic silica columns, the polymer monoliths are made of an organic polymer base. Dionex, traditionally known for its ion chromatography capabilities, has led this side of the field. Dionex first acquired a license for the polymeric monolith technology in the 1990s. Dionex also acquired ESA Biosciences' HPLC assets in 2009, expanding its expertise in this area.
By 1818, the United States Navy had outlined that each sailor was to be given 14 ounces (400 g) of bread per day as part of their daily ration while serving onboard in the form of hardtack. The procurement of these stores was the responsibility of the ship's Purser, and was not strictly outlined by the Board of Navy Commissioners. During the American Civil War (1861–1865), three-by-three-inch (7.6 by 7.6 cm) hardtack was shipped from Union and Confederate storehouses. Civil War soldiers generally found their rations to be unappealing; hardtack's ability to host worms earned it the "worm castles" nickname, and soldiers joked about the poor quality of the hardtack in the satirical song "Hard Tack Come Again No More". The song was sung to the tune of the Stephen Foster song "Hard Times Come Again No More", and featured lyrics describing the hardtack rations as being 'old and very wormy' and causing many 'stomachs sore'. John Billings, a soldier in the 10th Massachusetts Battery, outlines many details on how hardtack was utilized during the war in his book Hard Tack and Coffee.
Benzoctamine is a drug that possesses sedative and anxiolytic properties. Marketed as Tacitin by Ciba-Geigy, it is different from most sedative drugs because in most clinical trials it does not produce respiratory depression, but actually stimulates the respiratory system. As a result, when compared to other sedative and anxiolytic drugs such as benzodiazepines like diazepam, it is a safer form of tranquilizing. However, when co-administered with other drugs that cause respiratory depression, like morphine, it can cause increased respiratory depression. Medically, benzoctamine is used as a treatment for anxious outpatients to control aggression, enuresis, fear, and minor social maladjustment in children. Its anxiolytic effects are most similar to diazepam, another anxiolytic, but unlike diazepam, benzoctamine has antagonistic effects on epinephrine and norepinephrine, and appears to increase serotonin levels. While little is understood about how it carries out its effects, studies point to reduced serotonin, epinephrine, and norepinephrine as partial causes of its pharmacologic and behavioral effects. Animal studies have shown sedative hypnotic drugs tend to show dependency in animals, but benzoctamine has been shown to not be addictive. Other animal studies also point to the drug as a possible mechanism by which to reduce blood pressure through the adrenergic system. Chemically, benzoctamine belongs to the class of compounds called dibenzobicyclo-octadienes.
Sources: en.wikipedia.org
Galloway told Ahmadinejad: "I have police protection in London from the Iranian opposition because of my support for your election campaign" in 2009. "I mention this so you know where I'm coming from." In May 2025, Galloway was awarded the Ismail Haniyeh Prize at the Iranian state-organized Sobh International Media Festival, named after the assassinated former chairman of Hamas. In his acceptance speech, he praised Iranian Supreme Leader Ali Khamenei, stating: "I thank the revolutionary people of Iran, your leadership, your heroes, and your martyrs for standing firm in support of the Palestinian people."
== Usage and Applications == COBRA has been used extensively in many research-based applications such as screening for DNA methylation changes at gene promoters in cancer studies, detecting altered methylation patterns at imprinted genes, and characterizing methylation patterns in the genome during development in mammals. In medicine, COBRA has been used as a tool to help diagnose human disease involving aberrant DNA methylation. Researchers utilized COBRA in conjunction with denaturing high performance liquid chromatography in the diagnosis of the genetic imprinting disorder Russell-Silver syndrome where hypomethylation of the imprinted gene H19 is responsible for the disorder in up to 50% of patients.
=== Pharmacokinetics === Elexacaftor/tezacaftor/ivacaftor is primarily metabolized by CYP3A4 /5. This medication should be taken with a high fat meal to improve absorption through the gut. It is excreted as metabolites or unchanged mainly through feces and to a smaller extent urine. The mean effective half-life of elexacaftor, tezacaftor, and ivacaftor is 27.4 hours, 25.1 hours, and 15 hours, respectively.
== Further reading == "Biographical Entry: Dr. Martin Litchfield West"[link removed], Debrett's People of Today, Debrett's Limited, 18–20 Hill Rise, Richmond, Surrey TW10 6UA United Kingdom. Fries, Almut (2015). "Martin Litchfield West (1937–2015)". Studia Metrica et Poetica. 2 (2): 152–158. doi:10.12697/smp.2015.2.2.12. ISSN 2346-6901. Lightfoot, J. L. (September 2017). "Martin Litchfield West" (PDF). Proceedings of the American Philosophical Society. 161 (3): 285–292.
Sources: en.wikipedia.org
Mescaline acts as an agonist of the serotonin 5-HT2A receptor to produce its psychedelic effects. Its EC50Tooltip half-maximal effective concentration at the serotonin 5-HT2A receptor is approximately 10,000 nM and at the serotonin 5-HT2B receptor is greater than 20,000 nM. How activating the 5-HT2A receptor leads to psychedelic effects is still unknown, but it is likely that somehow it involves excitation of neurons in the prefrontal cortex. In addition to the serotonin 5-HT2A and 5-HT2B receptors, mescaline is also known to bind to the serotonin 5-HT2C receptor and a number of other targets. The drug shows pronounced biased agonism at the serotonin 5-HT2C receptor. Mescaline lacks affinity for the monoamine transporters, including the serotonin transporter (SERT), norepinephrine transporter (NET), and dopamine transporter (DAT) (Ki > 30,000 nM). However, it has been found to increase levels of the major serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) at high doses in rodents. This finding suggests that mescaline might inhibit the reuptake and/or induce the release of serotonin at such doses. In any case, this possibility has not yet been further assessed or demonstrated. Besides serotonin, mescaline might also weakly induce the release of dopamine, but this is probably of modest significance, if it occurs. In accordance, there is no evidence of the drug showing addiction or dependence. Mescaline appears to be inactive in terms of norepinephrine release induction and indirect sympathomimetic activity.
Many aspects of the structure-reactivity relationship in organic chemistry can be rationalized through resonance, electron pushing, induction, the eight electron rule, and s-p hybridization, but these are only helpful formalisms and do not represent physical reality. Due to these limitations, a true understanding of physical organic chemistry requires a more rigorous approach grounded in particle physics. Quantum chemistry provides a rigorous theoretical framework capable of predicting the properties of molecules through calculation of a molecule's electronic structure, and it has become a readily available tool in physical organic chemists in the form of popular software packages. The power of quantum chemistry is built on the wave model of the atom, in which the nucleus is a very small, positively charged sphere surrounded by a diffuse electron cloud. Particles are defined by their associated wavefunction, an equation which contains all information associated with that particle. All information about the system is contained in the wavefunction. This information is extracted from the wavefunction through the use of mathematical operators.
== Pharmacology == Valsartan is an angiotensin II receptor blocker this class of drug competes with angiotensin II for the angiotensin type I (AT1) receptors located throughout the body. Angiotensin II is a key component of the renin-angiotensin-aldosterone system which is responsible for vasoconstriction of blood vessels and promotes release of vasopressin from the posterior pituitary gland of the hypothalamus which helps promote water retention. Aldosterone is also released by the adrenal gland in response to angiotensin II which helps to reabsorb sodium which leads to water reabsorption that results in a rise in blood pressure. Blocking angiotensin II from binding to AT1 receptors will in turn prevent it from raising blood pressure which is why angiotensin II receptor blockers are useful medications in the treatment of blood pressure. Hydrochlorothiazide inhibits the NaCl co-transporters in the distal convoluted tubule of the nephrons located in the kidneys which are responsible for the excretion of sodium and chloride in exchange for reabsorption of calcium. Inhibition of the NaCl co-transporters result in water excretion which is believed to be the mechanism of action in diuresis and lowering blood pressure.
In 2003, Bakker began broadcasting The Jim Bakker Show daily at Studio City Café in Branson, Missouri, with his second wife Lori; it has been carried on CTN, Daystar, Folk TV, Grace Network (Canada), Daystar Television Canada, GEB America, Hope TV (Canada), Impact Network, WGN, WHT, TCT Network, The Word Network, UpliftTV, and ZLiving networks. Most of Bakker's audience receives his program on DirecTV and Dish Network. Bakker condemned the prosperity theology in which he took part earlier in his career, and has embraced apocalypticism. His show has a millennial, survivalist focus and sells buckets of freeze-dried food, such as beans on toast, to his audience in preparation for the end of days. Elspeth Reeve wrote in The Atlantic that Bakker's "doomsday survival gear" is overpriced. A man named Jerry Crawford, who credits Bakker with saving his marriage, invested $25 million in a new ministry for Bakker in Blue Eye, Missouri, named Morningside USA. Production for The Jim Bakker Show moved to Morningside in 2008.
Moreover, the ability to perform high frequency fractionation immediately from the eluent of a nano-LC column has greatly increases peak resolution and improved the overall separation quality when compared to continuous flow nano-LC devices. An HPLC column was first built directly into a microfluidic device by using TPE instead of PDMS for the device fabrication. The additional strength of TPE made it capable of supporting the higher pressures needed for HPLC such that a single, microfluidic lab-chip could perform chemical separation, fractionation, and further droplet manipulation. In order to increase the quality of chromatographic output, sturdier devices made of glass have shown the ability to withstand far greater pressure than TPE. Achieving these higher pressures to increase the degree of separation and eliminating all dead volumes through immediate droplet formation has shown the potential for droplet microfluidics to expand and improve the capabilities of HPLC separations.
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.
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。