The short version of GABA-A receptor fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-07-18. Anything still debated is marked as such rather than presented as settled.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
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.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
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.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Deaths may occur from overdose with this class of drugs. Multiple drug ingestion (including alcohol) is common in deliberate TCA overdose. As management of overdose is complex and changing, it is recommended that the physician contact a poison control center for current information on treatment. Signs and symptoms of toxicity develop rapidly after TCA overdose, therefore, hospital monitoring is required as soon as possible. Critical manifestations of overdose include: cardiac dysrhythmias, severe hypotension, convulsions, and CNS depression, including coma. Changes in the electrocardiogram, particularly in QRS axis or width, are clinically significant indicators of TCA toxicity. Other signs of overdose may include: confusion, disturbed concentration, transient visual hallucinations, dilated pupils, agitation, hyperactive reflexes, stupor, drowsiness, muscle rigidity, vomiting, hypothermia, hyperpyrexia.
Through US DOE ARPA-E's Nuclear Energy Waste Transmutation Optimized Now, or NEWTON program, the DOE aims to explore economically viable transmutation at a scale for transmutation of commercially used US nuclear fuel stockpile within 30 years mainly focusing on particle accelerator technology. The program expects to process used nuclear fuel to reduce the time it requires to reach radiotoxicity of natural uranium ore, from 100,000 years of cooling to 300 years. High energy proton beams are used in production of neutron beams through collision with heavy element target, like lead or bismuth, in a process called spallation. Reducing the size and cost of such setup is a major area of focus for practical viability of the process. 2018 Nobel Prize for Physics-winner Gérard Mourou has proposed using chirped pulse amplification to generate high-energy and low-duration laser pulses either to accelerate deuterons into a tritium target causing fusion events yielding fast neutrons, or accelerating protons for neutron spallation, with either method intended for transmutation of nuclear waste.
Glucagon is a hormone that generally opposes the action of insulin. It increases blood glucose by stimulating the production of glucose in the liver via glycogenolysis (breakdown of glycogen) and gluconeogenesis (production of glucose from non-carbohydrate sources). Glucagon also increases the breakdown of lipids and amino acids and the production of ketones. Unlike currently approved weight loss drugs, glucagon receptor agonists increase energy expenditure. Combination GLP-1/glucagon receptor agonists provide the thermogenic benefits of glucagon activation while almost eliminating hyperglycemia induced by glucagon receptor activation. Several such drugs have reached human trials for obesity, diabetes, and non-alcoholic fatty liver disease but adverse effects have hampered development. The most advanced of these drugs is mazdutide which is in a phase III trial as of 2023.
== See also == Maintenance respiration: maintenance as a functional component of cellular respiration Microphysiometry Pasteur point Respirometry: research tool to explore cellular respiration Tetrazolium chloride: cellular respiration indicator Complex 1: NADH:ubiquinone oxidoreductes
This is an example of the Nernst equation. The potential is known as a reduction potential. Standard electrode potentials are available in a table of values. Using these values, the actual electrode potential for a redox couple can be calculated as a function of the ratio of concentrations. The equilibrium potential for a general redox half-reaction (See #Equilibrium constant above for an explanation of the symbols)
Sources: en.wikipedia.org
=== United States === As of 2026, Whirlpool Corporation has 11 manufacturing plants throughout the United States, which employs about 15,000 workers. Approximately 80% of its U.S. product volume were manufactured domestically.
=== Automated insulin delivery === Tandem introduced Basal-IQ in 2018. The feature used predicted CGM values to suspend insulin delivery when glucose was expected to become low and resumed delivery when values recovered. Control-IQ is a hybrid closed-loop system that uses CGM readings and a model-predictive algorithm to increase, decrease or suspend basal insulin and to deliver automatic correction boluses. Users still program personal therapy settings and normally announce meals. The FDA authorized Control-IQ through the De Novo pathway in December 2019, creating a regulatory category for interoperable automated glycemic controllers. Tandem launched it in the United States in January 2020 as a software update for compatible t:slim X2 pumps. A revised version, Control-IQ+, broadened supported therapy settings and was cleared in 2025 for adults with type 2 diabetes who require insulin. In the United States, Control-IQ+ is used on both the t:slim X2 and Mobi platforms.
A number of natural toxins that interfere with actin's dynamics are widely used in research to study actin's role in biology. Latrunculin – a toxin produced by sponges – binds to G-actin preventing it from joining microfilaments. Cytochalasin D – produced by certain fungi – serves as a capping factor, binding to the (+) end of a filament and preventing further addition of actin molecules. In contrast, the sponge toxin jasplakinolide promotes the nucleation of new actin filaments by binding and stabilizing pairs of actin molecules. Phalloidin – from the "death cap" mushroom Amanita phalloides – binds to adjacent actin molecules within the F-actin filament, stabilizing the filament and preventing its depolymerization. Phalloidin is often labelled with fluorescent dyes to visualize actin filaments by fluorescence microscopy.
Despite its historical roots in hepatitis C research, the term "direct-acting antivirals" is currently used more broadly to describe all antiviral drugs with a viral protein as a target of action. Commonly used FDA-approved direct-acting antivirals include aciclovir which is used to treat herpes simplex virus, and letermovir which is used to treat cytomegalovirus. Aciclovir functions by competitively inhibiting viral DNA polymerase as well as inserting itself into the viral DNA chain terminating viral replication. Letermovir inhibits the viral DNA terminase complex that is responsible for cleaving viral DNA to be packaged into capsids. Both of these drugs bind to a specific viral protein, inhibiting the viral life cycle. DAAs have revolutionized treatment outcomes for hepatitis C and many other viral infections by improving treatment efficacy and reducing side effect profiles. However, a problem with DAAs is their low genetic barrier, the number of genetic mutations a virus needs to accumulate to develop resistance to the drug. RNA viruses have a uniquely unstable genome due to undergoing rapid replication with poor replication fidelity due to the absence of DNA polymerase proofreading capabilities. Since many DAAs target a single protein, one mutation is often enough to make a viral strain resistant to a DAA. For example, a single nucleotide substitution in the reverse transcriptase of HIV-1 severely reduces the efficiency of emtricitabine, a nucleoside reverse transcriptase inhibitor commonly used to suppress HIV-1 infection.
The ligated mRNA-DNA-puromycin library is translated in Red Nova Lysate (Novagen) or E. coli S30 Extract System (Promega), resulting in peptides covalently linked in cis to the encoding mRNA. The in vitro translation can also be done in a PURE (protein synthesis using recombinant elements) system. PURE system is an E. coli cell-free translation system in which only essential translation components are present. Some components, such as amino acids and aminoacyl-tRNA synthases (AARSs) can be omitted from the system. Instead, chemically acylated tRNA can be added into the PURE system. It has been shown that some unnatural amino acids, such as N-methyl-amino acid accylated tRNA can be incorporated into peptides or mRNA-peptide fusions in a PURE system. After translation, the single-stranded mRNA portions of the fusions will be converted to heteroduplex of RNA/DNA by reverse transcriptase to eliminate any unwanted RNA secondary structures, and render the nucleic acid portion of the fusion more stable. This step is a standard reverse transcription reaction. For instance, it can be done by using Superscript II (GIBCO-BRL) following the manufacturer's protocol.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.