If you have been reading about GABA-A receptor and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-04-14. Numbers and descriptions here follow the published literature rather than marketing material.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
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.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Panera Bread Company ( pə-NAIR-ə) is an American multinational chain of bakery-cafe fast casual restaurants with over 2,000 locations, all of which are in the United States and Canada. Its headquarters are in Fenton, Missouri. The chain operates as Saint Louis Bread Company in the Greater St. Louis area, with over 100 locations. Panera offers a wide array of pastries and baked goods, such as bagels, brownies, cookies, croissants, muffins, and scones. These, along with Panera's artisan breads, are typically baked by an on-staff baker the day before serving. Aside from the bakery section, Panera has a regular menu for dine-in or takeout, including salads, sandwiches, side choices, and soups, as well as coffee, espresso drinks, frozen drinks, fruit smoothies, hot chocolate, iced drinks, lattes, lemonade, and tea. Panera Bread, formerly owned by Au Bon Pain, is currently owned by JAB Holding Company, which is, in turn, owned by the Reimann family of Germany. Panera was once the largest provider of free Wi-Fi hotspots in the United States.
As it affects glycogenolysis, it has been suggested that it should re-designated as GSD-XIV. Lafora disease is considered a complex neurodegenerative disease and also a glycogen metabolism disorder. Polyglucosan storage myopathies are associated with defective glycogen metabolism (Not McArdle disease, same gene but different symptoms) Myophosphorylase-a activity impaired: Autosomal dominant mutation on PYGM gene. AMP-independent myophosphorylase activity impaired, whereas the AMP-dependent activity was preserved. No exercise intolerance. Adult-onset muscle weakness. Accumulation of the intermediate filament desmin in the myofibers of the patients. Myophosphorylase comes in two forms: form 'a' is phosphorylated by phosphorylase kinase, form 'b' is not phosphorylated. Both forms have two conformational states: active (R or relaxed) and inactive (T or tense). When either form 'a' or 'b' are in the active state, then the enzyme converts glycogen into glucose-1-phosphate. Myophosphorylase-b is allosterically activated by AMP being in larger concentration than ATP and/or glucose-6-phosphate. (See Glycogen phosphorylase§Regulation). Unknown glycogenosis related to dystrophy gene deletion: patient has a previously undescribed myopathy associated with both Becker muscular dystrophy and a glycogen storage disorder of unknown aetiology.
Creatine is an organic acid naturally occurring in the body (and in red meats) that supplies energy to muscle cells for short bursts of energy (as required in lifting weights) via creatine phosphate replenishment of ATP. Scientific studies have shown that creatine supplementation can increase the consumer's strength, energy during performance, muscle mass, and recovery times after exercise. In addition, recent studies have also shown that creatine improves brain function and reduces mental fatigue. Some studies have suggested that consumption of creatine with protein and carbohydrates can have a greater effect than creatine combined with either protein or carbohydrates alone. While generally considered safe, long-term or excessive consumption of creatine may have an adverse effect on the kidneys, liver, or heart and should be avoided if any pre-existing conditions affecting these organs exist.
Sources: en.wikipedia.org
According to NEWSru, on 8 August 2012 Russian president Vladimir Putin said to journalists: "It's no secret; there was a plan, and we acted within its framework. It was developed by the General Staff in late 2006 - early 2007 and agreed upon with me. As part of the plan, we trained South Ossetian militias".
The size of a burn is measured as a percentage of total body surface area (TBSA) affected by partial thickness or full thickness burns. First-degree burns that are only red in color and are not blistering are not included in this estimation. Most burns (70%) involve less than 10% of the TBSA. Unit of measuring burns is VSD as 10% TBSA is equal to 1VSD. There are a number of methods to determine the TBSA, including the Wallace rule of nines, Lund and Browder chart, and estimations based on a person's palm size. The rule of nines is easy to remember but only accurate in people over 16 years of age. More accurate estimates can be made using Lund and Browder charts, which take into account the different proportions of body parts in adults and children. The size of a person's handprint (including the palm and fingers) is approximately 1% of their TBSA.
=== France === This data pertains to reported medical cases of 23 specific pathogens in the 1990s, as opposed to total population estimates of all foodborne illness for the United States. In France, for 735,590 to 769,615 cases of infection identified as being with the 23 specific pathogens, 238,836 to 269,085 were estimated to have been contracted from food:
Sources: en.wikipedia.org
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.