heptapeptide 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 2025-11-08. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
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 |
|---|---|---|
| Molecular formula | C33H57N11O9 | Derived from the seven-residue sequence |
| Molecular weight | About 751.9 g/mol | Average mass; the monoisotopic value is slightly lower |
| Residue count | Seven amino acids | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent compound | Tuftsin (Thr-Lys-Pro-Arg) | Selank extends tuftsin at the C-terminus |
| Compound class | Synthetic short peptide | Studied in a research setting; not a licensed drug in most markets |
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 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.
==== Declined ==== Jasmine Crockett, incumbent U.S. representative (ran for U.S. Senate) Domingo García, former president of the League of United Latin American Citizens (2018–2024) and candidate for this district in 2012 Marc Veasey, incumbent U.S. representative from the 25th district (ran for Tarrant County judge)
=== Artistic === Blood is one of the body fluids that has been used in art. In particular, the performances of Viennese Actionist Hermann Nitsch, Istvan Kantor, Franko B, Lennie Lee, Ron Athey, Yang Zhichao, Lucas Abela and Kira O'Reilly, along with the photography of Andres Serrano, have incorporated blood as a prominent visual element. Marc Quinn has made sculptures using frozen blood, including a cast of his own head made using his own blood.
== Birman naming conventions == Many Birman breeders follow the French tradition of assigning all kittens born in a particular year given names that begin with the same letter of the alphabet. Countries with breeders using this convention include Australia, Canada, France, New Zealand, the U.K., and the U.S. Kittens born in 2016 would start with 'N', and in 2017 'O', and so on.
The second concerns the subject (quoad subiectum): the sickness of a person is judged incurable, in its course it can even have destroyed bones or vital organs; in this case not only is complete recovery noticed, but even wholesale reconstitution of the organs (restitutio in integrum). The third degree (quoad modum) involves instantaneous recovery from an illness that treatment could only have achieved after a long period. In 2016 Cardinal Parolin, under the mandate of Pope Francis, approved new Regulations for the Medical Board of the Congregation for the Causes of Saints. The Regulations were published and signed by Cardinal Amato and Archbishop Marcello Bartolucci.
The hemoglobin is metabolized to bilirubin (causing jaundice at high concentrations). The red cells rarely disintegrate in the circulation, so hemoglobin is rarely excreted directly by the kidney, but this can occur in severe cases, causing acute kidney injury. Deficiency of G6PD in the alternative pathway causes the buildup of glucose, and thus an increase of advanced glycation endproducts (AGE). The deficiency also reduces the amount of NADPH, which is required for nitric oxide (NO) synthesis. The high prevalence of diabetes mellitus type 2 and hypertension in Afro-Caribbeans in the West could be directly related to the incidence of G6PD deficiency in those populations. Although female carriers can have a mild form of G6PD deficiency (dependent on the degree of inactivation of the unaffected X chromosome – see Skewed X-inactivation), homozygous females have been described; in these females, there is co-incidence of a rare immune disorder termed chronic granulomatous disease (CGD).
Sources: en.wikipedia.org
Hundreds of thousands of tons of toxic debris containing more than 2,500 contaminants and known carcinogens were spread across Lower Manhattan when the towers collapsed. Exposure to the toxins in the debris is alleged to have contributed to fatal or debilitating illnesses among people who were at Ground Zero. The Bush administration ordered the Environmental Protection Agency (EPA) to issue reassuring statements regarding air quality in the aftermath of the attacks, citing national security, but the EPA did not determine that air quality had returned to pre–September 11 levels until June 2002. Health effects extended to residents, students, and office workers in Lower Manhattan and nearby Chinatown. Several deaths have been linked to the toxic dust, and victims' names were included in the World Trade Center memorial. An estimated 18,000 people have developed illnesses as a result of the toxic dust. There is also scientific speculation that exposure to toxic products in the air may have negative effects on fetal development. A study of rescue workers released in April 2010 found that all those studied had impaired lung function. Years after the attacks, legal disputes over the costs of related illnesses were still in the court system. In 2006, a federal judge rejected New York City's refusal to pay for health costs for rescue workers, allowing for the possibility of suits against the city. Government officials have been faulted for urging the public to return to lower Manhattan in the weeks shortly after the attacks.
=== Vector design === DNA vaccines elicit the best immune response when high-expression vectors are used. These are plasmids that usually consist of a strong viral promoter to drive the in vivo transcription and translation of the gene (or complementary DNA) of interest. Intron A may sometimes be included to improve mRNA stability and hence increase protein expression. Plasmids also include a strong polyadenylation/transcriptional termination signal, such as bovine growth hormone or rabbit beta-globulin polyadenylation sequences. Polycistronic vectors (with multiple genes of interest) are sometimes constructed to express more than one immunogen, or to express an immunogen and an immunostimulatory protein. Because the plasmid – carrying relatively small genetic code up to about 200 Kbp – is the "vehicle" from which the immunogen is expressed, optimising vector design for maximal protein expression is essential. One way of enhancing protein expression is by optimising the codon usage of pathogenic mRNAs for eukaryotic cells. Pathogens often have different AT-contents than the target species, so altering the gene sequence of the immunogen to reflect the codons more commonly used in the target species may improve its expression. Another consideration is the choice of promoter. The SV40 promoter was conventionally used until research showed that vectors driven by the Rous Sarcoma Virus (RSV) promoter had much higher expression rates.
== Synthesis == Etonitazene and related nitazene opioids were discovered in the late 1950s, by a team of Swiss researchers working at the pharmaceutical firm CIBA (now Novartis). One of the first compounds investigated by the Swiss team was 1-(β-diethylaminoethyl)-2-benzylbenzimidazole, which was found to possess 10% of the analgesic activity of morphine when tested in rodent bioassays. This finding encouraged the group to begin a comprehensive systematic study of 2-benzylbenzimidazoles and to establish the structure-activity relationship of this new family of analgesics. Two general synthetic methods were developed for the preparation of these compounds. The first method involved the condensation of o-phenylenediamine with para-ethoxy-phenylacetonitrile to form a 2-benzylbenzimidazole. The benzimidazole is then alkylated with the desired 1-chloro-2-dialkylaminoethane, forming the final product. This particular procedure was most useful for the preparation of benzimidazoles that lacked substituents on the benzene rings. A diagram of this method is displayed below.
Glenn experienced no such difficulties, and it was determined that microgravity did not affect the natural swallowing process, which is enabled by the peristalsis of the esophagus. Astronauts in later Mercury missions (1959–1963) disliked the food that was provided. They ate bite-sized cubes, freeze-dried powders, and tubes of semiliquids. The astronauts found it unappetizing, experienced difficulties in rehydrating the freeze-dried foods, and did not like having to squeeze tubes or collect crumbs. Prior to the mission, the astronauts were also fed low residual launch-day breakfasts to reduce the chances that they would defecate in flight.
Sources: en.wikipedia.org
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.
Tuftsin contains four residues, while selank carries an additional Pro-Gly-Pro segment at the carboxyl end. That extension is intended to reduce enzymatic cleavage. Comparative pharmacokinetic data in humans remain limited.
No single receptor target is widely accepted as the definitive mediator of the reported effects. Proposed contributors include GABAergic modulation, shifts in monoamine turnover, and altered neuropeptide degradation. The mechanism is treated in the literature as unresolved.
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.