The short version of GABA-A receptor fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
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, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
| 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 |
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.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
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.
16 June – Researchers report an fMRI study (31 May) that identifies circuitries and changes which may be crucial for consciousness in humans – or the loss and the recovery thereof in disorders of consciousness e.g. in coma patients. 17 June – Researchers report that a single gas-stove burner can raise the indoor concentrations of benzene, related to cancer risk, to more than that found in secondhand tobacco smoke. 19 June – Researchers review research on the substantial links between social isolation (HR ~1.32) and loneliness (HR ~1.14) and mortality. 21 June – The first successful transplant of a functional cryopreserved mammalian kidney is reported. The study demonstrates a "nanowarming" technique for vitrification for up-to-100 days preservation of transplant organs. 22 June – A study projects that by 2050, the worldwide number of adults with diabetes will more than double, from 529 million to over 1.3 billion. No country is expected to see a decline. 26 June Retatrutide, an experimental drug against obesity, is shown to achieve a more than 24% mean weight reduction in human adults during a Phase 2 trial. Astronomers detect, for the first time, methenium, CH3+ (and/or carbon cation, C+), basic ingredients of life as we know it, in interstellar space. 28 June Astronomers report the possible detection of a gravitational wave background (GWB) in the Universe. A study with controlling finds substantial links between reading for pleasure during childhood and later cognition.
== Diet == There is no one food or nutrient capable of providing adequate bone health on its own. Instead, a balanced diet sufficient in fruits and vegetables for their vitamins, minerals, and alkalinizing substrates is thought to be most beneficial. High protein diets supply larger amounts of amino acids that could be degraded to acidic compounds. Protein consumption above the Recommended Dietary Allowance is also known to be beneficial to calcium utilization. Overall, it is understood that high-protein diets have a net benefit for bone health because changes in IGF-I and PTH concentrations outweigh the negative effects of metabolic acid production. The source of protein, plant or animal, does not matter in terms of acid produced from amino acid metabolism. Any differences in methionine and cysteine content is not significant to affect the overall potential renal acid load (PRAL) of the food. In addition to their acid precursor protein content, plants also contain significant amounts of base precursors. Potassium bicarbonate, a basic salt, is produced via the metabolism of other organic potassium salts: citrate, malate, and gluconate, which are substantial in plants. The discrepancy observed in PRAL is accounted for by differences in base precursor content.
==== Niche uses ==== There are thousands of uses of various potassium compounds. One example is potassium superoxide, KO2, an orange solid that acts as a portable source of oxygen and a carbon dioxide absorber. It is widely used in respiration systems in mines, submarines and spacecraft as it takes less volume than the gaseous oxygen.
Sources: en.wikipedia.org
While it was known that plants expressing virus-specific proteins showed enhanced tolerance or resistance to viral infection, it was not expected that plants carrying only short, non-coding regions of viral RNA sequences would show similar levels of protection. Researchers believed that viral RNA produced by transgenes could also inhibit viral replication. The reverse experiment, in which short sequences of plant genes were introduced into viruses, showed that the targeted gene was suppressed in an infected plant. This phenomenon was labeled "virus-induced gene silencing" (VIGS), and the set of such phenomena were collectively called post transcriptional gene silencing. After these initial observations in plants, laboratories searched for this phenomenon in other organisms. The first instance of RNA silencing in animals was documented in 1996, when Guo and Kemphues observed that, by introducing sense and antisense RNA to par-1 mRNA in Caenorhabditis elegans caused degradation of the par-1 message. It was thought that this degradation was triggered by single-stranded RNA (ssRNA), but two years later, in 1998, Fire and Mello discovered that this ability to silence the par-1 gene expression was actually triggered by double-stranded RNA (dsRNA). Craig C. Mello and Andrew Fire's 1998 Nature paper reported a potent gene silencing effect after injecting double stranded RNA into C. elegans.
== Structure == Parafollicular cells are pale-staining cells found in small number in the thyroid and are typically situated basally in the epithelium, without direct contact with the follicular lumen. They are always situated within the basement membrane, which surrounds the entire follicle.
=== Contraindications === Ceftriaxone should not be used in those with an allergy to ceftriaxone or any component of the formulation. Although there is negligible cross-reactivity between penicillins and third-generation cephalosporins, caution should still be used when using ceftriaxone in penicillin-sensitive patients. Caution should be used in people who have had previous severe penicillin allergies. It should not be used in hyperbilirubinemic neonates, particularly those who are premature because ceftriaxone is reported to displace bilirubin from albumin binding sites, potentially causing bilirubin encephalopathy. Concomitant use with intravenous calcium-containing solutions/products in neonates (≤28 days) is contraindicated even if administered through different infusion lines due to rare fatal cases of calcium-ceftriaxone precipitations in neonatal lungs and kidneys.
Sources: en.wikipedia.org
=== Books === Two biographies have been written about Staley, both authored by Adriana Rubio—Layne Staley: Angry Chair released in 2003, which contains an alleged final interview of Staley that Rubio claimed to have conducted less than three months before his death, and Layne Staley: Get Born Again, released in 2009, a revised and updated version of her earlier book. Staley's family has disputed Rubio's work, stating they do not believe she interviewed him in 2002. When questioned about the authenticity of the book, Rubio refused to confirm the interview was genuine. Staley's last interview was for the radio program Rockline on July 19, 1999, promoting the release of the compilation album Nothing Safe: Best of the Box with the other members of Alice in Chains. The content of Rubio's book, including what she referred to as Staley's final interview, was called into question in journalist David De Sola's 2015 book Alice in Chains: The Untold Story. De Sola questions not only the content of the interview, which portrays Staley as using his lyrics in casual conversation, it also indicates that Rubio never spoke to him, citing her refusal to release the tape with the interview and the fact that not even her publisher had access to the tape. One of Staley's sisters, Liz Coats, likewise doubted the veracity of the book. Staley was featured on the books Grunge Is Dead: The Oral History of Seattle Rock Music (2009) by Greg Prato, and Everybody Loves Our Town: An Oral History of Grunge (2011) by Mark Yarm.
It was instrumental in the Red Terror and Great Purge, but was brought under strict party control after Stalin's death. Under Yuri Andropov, the KGB engaged in the suppression of political dissent and maintained an extensive network of informers, reasserting itself as a political actor to some extent independent of the party-state structure, culminating in the anti-corruption campaign targeting high-ranking party officials in the late 1970s and early 1980s.
=== Causative genetic mutations and phenotypic expressions === Hereditary spherocytosis is caused by a variety of molecular defects in the genes that code for the red blood cell proteins spectrin (alpha and beta), ankyrin, band 3 protein, protein 4.2, and other red blood cell membrane proteins:
g(l) and g(s) are g-factors of the nucleons. Since the proton and neutron have different values for g(l) and g(s), one must separate their contributions. Each gets half of the deuterium orbital angular momentum
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.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.