elevated plus maze comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-03-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Principal proposed target | GABA-A receptor complex | Hypothesis derived mainly from animal pharmacology |
| Common behavioral assay | Elevated plus maze | Rodent test for anxiety-like behavior |
| Reported molecular marker | Hippocampal BDNF expression | Measured by immunoassay or mRNA quantification |
| Typical dosing route | Intranasal | Chosen to reduce first-pass metabolism |
| Reported plasma half-life | Minutes | Based on limited peptide stability data |
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
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.
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.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
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.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
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.
=== Outside mainland China === PRC Customs said exports of dairy products and eggs in 2007 were valued at US$359 million, a year-on-year increase of 90 per cent. Since the news of the melamine contamination began to circulate, at least 25 countries stopped importing Chinese dairy products. A number of countries had imposed blanket bans on Chinese milk products or its derivatives—among which were Bangladesh, Bhutan, Brunei, Burundi, Cameroon, Chile, Colombia, Dominican Republic, Gabon, India, Côte d'Ivoire, Maldives, Mali, Mexico, Nepal, Papua New Guinea, Paraguay, South Korea, Suriname, Tanzania, Togo, and the United Arab Emirates —joining Indonesia, Taiwan, Japan, Singapore and Malaysia which had also imposed specific bans on Chinese dairy products which tested positive for melamine.
== Prevention == Passive recovery, instead of active recovery, is a form of rest that is recommended to be performed by athletes in between rigorous, intermittent exercise. With active recovery, time to exhaustion is much shorter because the muscles are deoxygenated at a much quicker rate than with passive recovery. Thus, if avoiding overtraining means preventing exhaustion, passive recovery or "static rest" is safest. "Five weeks of rest appreciably improve both performance and mood state, and there is growing evidence that a very low level of exercise will speed recovery." If active recovery is performed during intense exercise, an athlete may find themselves in a state of being overtrained. The gradual variation of intensity and volume of training is also an effective way to prevent overtraining.
Note: For purposes of this table, genes are defined as orphan genes (when species-specific) or TRGs (when limited to a closely related group of species) when the mechanism of origination has not been investigated, and as de novo genes when de novo origination has been inferred, irrespective of method of inference. The designation of de novo genes as "candidates" or "proto-genes" reflects the language used by the authors of the respective studies.
== Analysis == The identification and quantitation of unsaturated fats is a well developed science. The degree of unsaturation of a sample is indicated by the iodine value or iodine number, the degree to which a fat adds iodine. The identification of individual fatty acids, saturated and saturated, that comprise a fat usually entails transesterification to give fatty acid methyl esters (FAMEs), which are amenable to separation and quantitation using gas chromatography. Classically, unsaturated isomers were separated and identified by argentation thin-layer chromatography.
Sources: en.wikipedia.org
Rn(g) + 2 [O2]+[SbF6]−(s) → [RnF]+[Sb2F11]−(s) + 2 O2(g) For this reason, antimony pentafluoride together with chlorine trifluoride and N2F2Sb2F11 have been considered for radon gas removal in uranium mines due to the formation of radon–fluorine compounds. Radon compounds can be formed by the decay of radium in radium halides, a reaction that has been used to reduce the amount of radon that escapes from targets during irradiation. Additionally, salts of the [RnF]+ cation with the anions SbF6−, TaF6−, and BiF6− are known. Radon is also oxidised by dioxygen difluoride to RnF2 at 173 K (−100 °C; −148 °F). Radon oxides are among the few other reported compounds of radon; only the trioxide (RnO3) has been confirmed. The higher fluorides RnF4 and RnF6 have been claimed, are calculated to be stable, but have not been confirmed. They may have been observed in experiments where unknown radon-containing products distilled together with xenon hexafluoride: these may have been RnF4, RnF6, or both. Trace-scale heating of radon with xenon, fluorine, bromine pentafluoride, and either sodium fluoride or nickel fluoride was claimed to produce a higher fluoride as well which hydrolysed to form RnO3. While it has been suggested that these claims were really due to radon precipitating out as the solid complex [RnF]2+[NiF6]2−, the fact that radon coprecipitates from aqueous solution with CsXeO3F has been taken as confirmation that RnO3 was formed, which has been supported by further studies of the hydrolysed solution.
does not hold if the flow is not stationary or it is not conservative, it does hold on average if the flow is steady and conservative on average, and not necessarily at any instant. Under such conditions, which are common in queueing theory and supply chain management, the relation is known as Little's Law.
== Poets == Dannie Abse, poet and physician Al Alvarez, poet Marc Bolan (born Mark Feld; 30 September 1947 – 16 September 1977); guitarist, singer, songwriter and poet; in 1969, wrote a collection of poems entitled The Warlock of Love; of Russian Jewish and Polish Jewish ancestry, Bolan was pioneer of glam rock movement in early 1970s with T. Rex; was inducted into the Rock and Roll Hall of Fame in 2020. Ivor Cutler, poet, humorist, musician Aviva Dautch, poet Elaine Feinstein, poet, writer, biographer Rose Fyleman, children's writer Karen Gershon, German-born poet Yvonne Green, (8 April 1957 – 16 April 2024) was an English poet, translator, writer and barrister. She was an Orthodox Jew, of Bukharian Jewish ancestry. Her first pamphlet, Boukhara, was published in 2007 and won The Poetry Business 2007 Book & Pamphlet Competition. Her first full-length collection, The Assay was published in 2010 and as a result of an award from Celia Atkin and Lord Gavron was translated into Hebrew in 2013, under the title HaNisuyi and published in Israel by Am Oved. Philip Hobsbaum, poet Jenny Joseph, poet Denise Levertov (1923-1997), British-born, naturalised American poet, feminist and anti-war activist. Amy Levy, poet and novelist Mina Loy (1882–1966); of Hungarian Jewish ancestry; artist, writer, poet, playwright, novelist, painter, designer, and bohemian; first-generation modernist; her poetry admired by T. S.
Sources: en.wikipedia.org
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.
Behavioral endpoints include time spent in open arms of the elevated plus maze and avoidance latencies. Biochemical endpoints include BDNF concentration, cytokine levels, and monoamine metabolite ratios in brain tissue.
Most published studies are small, originate from a limited number of laboratories, and lack independent replication. Dose-response relationships, measured brain exposure, and long-term outcomes are not well characterized.
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.