The short version of BDNF fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-09-10 and is reviewed periodically as new material appears.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
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.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
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.
==== Static vs. dynamic freezing profiles ==== If a freeze casting setup with a constant temperature on either side of the freezing system is used, (static freeze-casting) the front solidification velocity in the SSZ will decrease over time due to the increasing thermal buffer caused by the growing ice front. When this occurs, more time is given for the anisotropic ice crystals to grow perpendicularly to the freezing direction (c-axis) resulting in a structure with ice lamellae that increase in thickness along the length of the sample.
== June 24, 1915 (Thursday) == The Harry Elkins Widener Memorial Library was dedicated on Commencement Day at Harvard University, in memory of Harvard graduate and book collector Harry Elkins Widener, who died during the sinking of the RMS Titanic on April 15, 1912. Born: Fred Hoyle, British astronomer, leading theorist on stellar nucleosynthesis and the rejection of the Big Bang theory; in Gilstead, England (d. 2001)
substrate 1. A chemical compound or molecule upon which a particular enzyme directly acts, often but not necessarily binding the molecule by forming one or more chemical bonds. See also ligand. 2. The substance, biotic or abiotic, upon which an organism grows or lives, or by which it is supported; e.g. a particular growth medium used in cell culture. See also substratum.
In the quarterfinals, he beat Borna Ćorić in four sets to reach his second major semifinal. There, he lost the first two sets to Pablo Carreño Busta, but came back to win the match in five; this was his first-ever match win from two sets down. He thus advanced to his first major final, where he faced Dominic Thiem. He became the runner-up, losing the final in a final-set tiebreaker despite leading by two sets and twice coming within two points of the title in the final set. Zverev was seeded 6th at the French Open. He beat Dennis Novak, Pierre-Hugues Herbert, and Marco Cecchinato, before losing in four sets to Jannik Sinner. In October, he won two consecutive ATP 250 events in Cologne, which took place in the 2020 ATP Tour because of the cancellation of several tournaments due to the COVID-19 pandemic. In the finals, he defeated Félix Auger-Aliassime and Diego Schwartzman, both in straight sets. Zverev then reached the final of the Paris Masters, beating Nadal in straight sets in the semifinals, where he lost to Daniil Medvedev in three sets. In the ATP Finals, Zverev was eliminated in the group stage after a three-set win over Diego Schwartzman, and straight-set losses to Djokovic and the eventual champion Medvedev.
Sources: en.wikipedia.org
There are many thousands of variants of SARS-CoV-2, which can be grouped into the much larger clades. Several different clade nomenclatures have been proposed. Nextstrain divides the variants into five clades (19A, 19B, 20A, 20B, and 20C), while GISAID divides them into seven (L, O, V, S, G, GH, and GR). Several notable variants of SARS-CoV-2 emerged in late 2020. The World Health Organization has currently declared five variants of concern, which are as follows:
before HAART, with a paucity of cerebrospinal fluid (CSF) inflammation and defects in antigen clearance; during initial HAART immune recovery, with pro-inflammatory signaling by antigen-presenting cells without an effector response; and at IRIS, a cytokine storm with a predominant type-1 helper T-cell interferon-gamma response. Three clinical predictors of cryptococcal-related paradoxical IRIS risk include:
=== 2010s === Stanton was elected into the Essendon leadership group for the 2010 season. Stanton amassed 477 possessions and kicked 13 goals in 20 games for an Essendon team which won seven matches and lost fifteen in a year that would see their coach, Matthew Knights, sacked one day after the conclusion of the regular season. Stanton polled six votes in the Brownlow Medal and finished fifth in the 2010 Crichton Medal with 167 votes. Stanton continued to improve during the year. Stanton led the club in kicks and handballs received and was in the top five for marks, handballs, inside-50s, rebound-50s and loose-ball gets. Into his ninth AFL season and in the Essendon leadership group, Stanton finished second in the 2011 Crichton Medal behind David Zaharakis. He played his 150th AFL game against Melbourne in Round 11. Wearing the number 5, his running and ability to accumulate possessions contributed to every victory during the 2012 season. He has now polled a career high 14 votes in the 2012 Brownlow Medal. In Round 6 of the 2012 AFL season, Stanton collected a record 193 Dream Team points in Essendon's win against the Brisbane Lions at Docklands Stadium. His statistics included: 39 disposals (from 32 kicks and 7 handballs), 17 marks and 8 tackles. As of 2015, it remains the highest Dream Team score by a midfielder. Stanton played his 200th game in Round 20, 2013 against West Coast at Etihad Stadium.
Sources: en.wikipedia.org
=== Pharmacodynamics === para-Chlorophenethylamine acts primarily as a serotonin-releasing agent with an EC50Tooltip Half maximal effective concentration value of 430 nM for the serotonin transporter, approximately the dose required to induce serotonin syndrome with seizures, tremor, and hyperthermia in mice, is quite low compared to other derivatives (such as ortho-chlorophenethylamine and meta-chlorophenethylamine) In mice with serotonin syndrome induced by para-chlorophenethylamine, the following symptoms were observed: lateral head bobbing, a Straub tail reaction, abduction of the hind limbs, tremors, hyperactivity, mutual pawing with the front paws, salivation, and piloerection. It acts as a full, weak agonist of TAAR with an EC50 value of 2,900 ± 1,000 nM. In vitro, it inhibited the activity of the enzyme phenylethanolamine N-methyltransferase. Para-chlorophenelethylamine stimulated 5-HT receptors.
== Biological role == Cadmium has no known function in most organisms, and is toxic. Cadmium is considered an environmental pollutant hazardous to living organisms. A cadmium-dependent carbonic anhydrase has been found in some marine diatoms, which live in environments with low zinc concentrations. Exposure to cadmium leads to raised levels in the blood cells for a number of months. In vertebrates cadmium is preferentially absorbed in the kidneys but also in the liver and bones. Up to about 30 mg of cadmium is commonly inhaled throughout human childhood and adolescence. Cadmium is eliminated from the body in very small amounts and mainly through urine resulting in a biological half-life of 20 to 40 years. Cadmium is under research for its potential toxicity to increase the risk of cancer, cardiovascular disease, and osteoporosis.
As of November 2024 he is not listed as part of the National Institute on Aging's staff on their website, although in November 2024 his name still appeared in NIH's Network Enterprise Directory, suggesting he was still an NIH employee.
Very low voltages are inefficient since the lead wires would conduct too much heat away from the filament, so the practical lower limit for incandescent lamps is 1.5 volts. Very long filaments for high voltages are fragile, and lamp bases become more difficult to insulate, so lamps for illumination are not made with rated voltages over 300 volts. Some infrared heating elements are made for higher voltages, but these use tubular bulbs with widely separated terminals.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.