BDNF 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 2025-07-21 and is reviewed periodically as new material appears.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid form |
| Solubility class | Freely soluble in water | Hydrophilic heptapeptide |
| Dry storage temperature | -20 degrees Celsius or lower | Sealed, desiccated, protected from light |
| Solution storage | 2 to 8 degrees Celsius short term | Avoid repeated freeze-thaw cycles |
| Common identification method | Reversed-phase HPLC with mass spectrometry | Confirms purity and molecular mass |
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
1st Airborne Battle Group (ABG), 187th Infantry (reassigned from the 24th Infantry Division on 8 February 1959)(1) 1st ABG, 325th Infantry 2nd ABG, 501st Infantry 1st ABG, 503d Infantry (reassigned from the 24th Infantry Division on 1 July 1958)(2) 2nd ABG, 503rd Infantry (reassigned to the 25th Infantry Division on 24 June 1960) 1st ABG, 504th Infantry (reassigned to the 8th Infantry Division on 11 December 1958) 2nd ABG, 504th Infantry (assigned effective 9 May 1960)(1) 1st ABG, 505th Infantry (reassigned to the 8th Infantry Division on 15 January 1959) (1) 1st ABG, 504th Infantry and 1st ABG, 505th Infantry were reassigned to the 8th Infantry Division in central West Germany to provide airborne capability in Germany; in turn, 1–187th and 1-503d were reassigned from the 24th Infantry Division in southern Germany to the 82nd Airborne Division (2) 2nd ABG, 503rd Infantry was reassigned to the 25th Infantry Division and stationed in Okinawa to provide airborne capability in the Pacific on 24 June 1960. This ABG was reassigned to the 173d Airborne Brigade on 26 March 1963.
There are over 800 extant species of cephalopod, although new species continue to be described. An estimated 11,000 extinct taxa have been described, although the soft-bodied nature of cephalopods means they are not easily fossilised. Cephalopods are found in all the oceans of Earth. None of them can tolerate fresh water, but the brief squid, Lolliguncula brevis, found in the Chesapeake Bay, is a notable partial exception in that it tolerates brackish water. Cephalopods are thought to be unable to live in fresh water due to multiple biochemical constraints, and in their >400 million year existence have never ventured into fully freshwater habitats. Cephalopods occupy most of the depth of the ocean, from the abyssal plains to the sea surface, and have also been found in the hadal zone. Their diversity is greatest near the equator (~40 species retrieved in nets at 11°N by a diversity study) and decreases towards the poles (~5 species captured at 60°N).
Elosulfase alfa, sold under the brand name Vimizim, is a medication used for the treatment of Morquio syndrome which is caused by a deficiency in the enzyme N-acetylgalactosamine-6-sulfatase. Elosulfase alfa is a synthetic version of this enzyme. Elosulfase alfa was developed by BioMarin Pharmaceutical Inc. and approved for use in the US by the Food and Drug Administration in 2014. Elosulfase alfa is used in enzyme replacement therapy; a 2014 study confirmed it was effective on young patients with Morquio syndrome type A. Treatment with this medication was most effective upon respiratory symptoms, activities of daily living and growth, as confirmed in a 2015 paper. The cost of elosulfase alfa in some countries is $2,080,000-$6,240,000 a year, which has made it difficult for some health systems to afford it. In June 2019, a Belgian court issued a preliminary injunction forcing BioMarin to continue supplying Vimizim to a young girl suffering from Morquio syndrome free of charge. BioMarin stopped providing the drug for free at the beginning of the year after negotiations with Belgian health authorities regarding reimbursement of the product repeatedly failed. This caused the parents to start legal proceedings to force the company to keep providing the medicine free of charge. BioMarin was ordered to keep doing so until a definitive judgment would be rendered, or until the medicine would be available on the Belgian market at a reasonable price.
Physical exercise is often recommended as a means of improving motor skills, fitness, muscle and bone strength, and joint function. Exercise has several effects upon muscles, connective tissue, bone, and the nerves that stimulate the muscles. One such effect is muscle hypertrophy, an increase in size of muscle due to an increase in the number of muscle fibers or cross-sectional area of myofibrils. Muscle changes depend on the type of exercise used. Generally, there are two types of exercise regimes, aerobic and anaerobic. Aerobic exercise (e.g. marathons) involves activities of low intensity but long duration, during which the muscles used are below their maximal contraction strength. Aerobic activities rely on aerobic respiration (i.e. citric acid cycle and electron transport chain) for metabolic energy by consuming fat, protein, carbohydrates, and oxygen. Muscles involved in aerobic exercises contain a higher percentage of Type I (or slow-twitch) muscle fibers, which primarily contain mitochondrial and oxidation enzymes associated with aerobic respiration. On the contrary, anaerobic exercise is associated with activities of high intensity but short duration, such as sprinting or weight lifting. The anaerobic activities predominately use Type II, fast-twitch, muscle fibers. Type II muscle fibers rely on Gluconeogenesis for energy during anaerobic exercise. During anaerobic exercise, type II fibers consume little oxygen, protein and fat, produce large amounts of lactic acid and are fatigable.
Sources: en.wikipedia.org
=== Classical philosophy === When the word "anarchy" (Greek: αναρχία, romanized: anarchia) was first defined in ancient Greece, it initially had both a positive and negative connotation, respectively referring to spontaneous order or chaos without rulers. The latter definition was taken by the philosopher Plato, who criticised Athenian democracy as "anarchical", and his disciple Aristotle, who questioned how to prevent democracy from descending into anarchy. Ancient Greek philosophy initially understood anarchy to be a corrupted form of direct democracy, although it later came to be conceived of as its own form of political regime, distinct from any kind of democracy. According to the traditional conception of political regimes, anarchy results when authority is derived from a majority of people who pursue their own interests.
The Federal Research Division estimated that the 86% of the population that did not consider themselves part of one of the ethnic groups indicated by the 2006 census was divided into 49% Mestizo or of mixed European and Amerindian ancestry, and 37% White, mainly of Spanish lineage, but there is also a large population of Middle East descent; in some sectors of society there is a considerable input of German and Italian ancestry. Many of the Indigenous peoples experienced a reduction in population during the Spanish rule and many others were absorbed into the mestizo population, but the remainder currently represents over eighty distinct cultures. Reserves (resguardos) established for indigenous peoples occupy 30,571,640 hectares (305,716.4 km2) (27% of the country's total) and are inhabited by more than 800,000 people. Some of the largest indigenous groups are the Wayuu, the Paez, the Pastos, the Emberá and the Zenú. The departments of La Guajira, Cauca, Nariño, Córdoba and Sucre have the largest indigenous populations. The Organización Nacional Indígena de Colombia (ONIC), founded at the first National Indigenous Congress in 1982, is an organization representing the indigenous peoples of Colombia. In 1991, Colombia signed and ratified the current international law concerning indigenous peoples, Indigenous and Tribal Peoples Convention, 1989. Sub-Saharan Africans were brought as slaves, mostly to the coastal lowlands, beginning early in the 16th century and continuing into the 19th century. Large Afro-Colombian communities are found today on the Pacific Coast.
== Metabolism == Metabolism of 1,3-dibromopropane was examined in 1981. The examination was done by orally administering 1,3-dibromopropane to rats and collecting results 24 hours after administration. Results were obtained from three sources: urine, faeces, and expired air. Upon analysis of the urinary results, researchers discovered the formation of metabolite, N-acetyl-S-(1-bromo-3-propyl)-cysteine and the decline in the GSH content of the liver of the rats. This led to the assumption that 1,3-dibromopropane could have reacted with GSH after administration and gave rise to 1-bromo-3-propyl-S-glutathione, which ultimately form the urinary metabolite. Moreover, due to little radioactivity observed from feces and the confirmation from maintained blood levels of radioactivity proved the occurrence of biliary excretion of sulfur-containing metabolites and enterohepatic cycling.
Actin, gamma-enteric smooth muscle is a protein that in humans is encoded by the ACTG2 gene. Actins are highly conserved proteins that are involved in various types of cell motility, and maintenance of the cytoskeleton. In vertebrates, three main groups of actin isoforms, alpha, beta and gamma have been identified. The alpha actins are found in muscle tissues and are a major constituent of the contractile apparatus. The beta and gamma actins co-exist in most cell types as components of the cytoskeleton, and as mediators of internal cell motility. Actin, gamma 2, encoded by this gene, is a smooth muscle actin found in enteric tissues. ACTG2 has been shown to interact with Emerin. Human ACTG2 genome location and ACTG2 gene details page in the UCSC Genome Browser.
Troika attempted to equalize the disciplines, keeping the effect intact and normalizing the cost, so a first-level power requires one blood point, a second-level two points, and so on. To balance the clans, the aristocratic Ventrue were only allowed to feed on noble blood, though this was changed to allow them to feed on lower-class humans, receiving less blood. During character creation, the game had an optional character biography with unique positive and negative characteristics (increasing one ability while limiting another). This was removed from the released game; Activision felt there was insufficient test time, and removing it was a more stable option. The team's previous experience was with turn-based combat games, and it struggled to develop a real-time combat system affected by customizable attributes and abilities that provided feedback to the player on how those statistics affected the battle. It initially found that by adhering too closely to the White Wolf source material rules for guns, where the effectiveness of a shot is determined in a contest between the player's skill and the opponent's defense, the firearms seemed broken; the player would not hit where they aimed. Troika found it difficult to mesh the available factors in a real-time setting. Melee combat had to deal with various melee weapons and animations and adjust for melee-on-melee and melee-on-ranged combat. Troika used first-person perspective to immerse the player in the setting, interacting face-to-face with the characters and seeing their facial reactions to the player.
Sources: en.wikipedia.org
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.
Reversed-phase HPLC establishes purity, while mass spectrometry confirms the expected molecular mass. Sequence confirmation may use tandem mass spectrometry or peptide mapping. A certificate of analysis typically reports these results alongside the analytical method applied.
In Russia it is a registered medicine available by prescription. In many other countries it is not approved for human use and is supplied only as a research chemical. Import and possession rules differ by jurisdiction, and buyers are responsible for checking local requirements.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.