The short version of heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-06-07 and is reviewed periodically as new material appears.
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.
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.
| 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 |
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.
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.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
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.
Yohimbine is a substance found in the bark of yohim trees in West Africa. It was traditionally used in West African cultures, in which the bark would be boiled and the resulting water drunk until it increased sexual desire. It is also found in over-the-counter health products. Yohimbine is an indole alkaloid and is an adrenoceptor antagonist. Known adverse effects include nausea, anxiety, irregular heartbeats, and restlessness.
The two substrates of this enzyme are (R)-2-hydroxystearic acid and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 2-oxostearic acid, reduced NADH, and a proton. This reaction is important in fatty acid metabolism. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (R)-2-hydroxystearate:NAD+ oxidoreductase. Other names in common use include D-2-hydroxy fatty acid dehydrogenase, and 2-hydroxy fatty acid oxidase.
NH4CO2NH2 ⇌ CO(NH2)2 + H2O (ΔH = 15.5 kJ/mol at 160–180 °C (320–356 °F)) The overall conversion of NH3 and CO2 to urea is exothermic, with the reaction heat from the first reaction driving the second. The conditions that favor urea formation (high temperature) have an unfavorable effect on the carbamate formation equilibrium. The process conditions are a compromise: the ill-effect on the first reaction of the high temperature (around 190 °C (374 °F)) needed for the second is compensated for by conducting the process under high pressure (1.4–1.75 MPa (203–254 psi)), which favors the first reaction. Although it is necessary to compress gaseous carbon dioxide to this pressure, the ammonia is available from the ammonia production plant in liquid form, which can be pumped into the system much more economically. To allow the slow urea formation reaction time to reach equilibrium, a large reaction space is needed, so the synthesis reactor in a large urea plant tends to be a massive pressure vessel.
The requirement to remove surfactants, specifically SDS as used in Gel Elution Liquid-based Fractionation Entrapment Electrophoresis fractionation, prior to LC means that some proteoforms will be lost due to a lack of solubility after surfactant removal.
The effects of microplastics on human health are a subject of ongoing study. These extremely small plastic particles originate from larger plastics and have been detected in high volumes in human biological samples, air, water, and food. This has raised concerns about the long-term impacts on human health. Plastic particles smaller than 5mm are considered microplastics (MPs). Particles smaller than 1μm are nanoplastics (NP), which are too small to be seen by the human eye. Nanoplastics remain less studied than larger plastic debris, and their long-term health impacts are still being investigated. Given their minute size, nanoplastics can penetrate biological barriers and accumulate in human tissues, raising questions about potential health effects. Micro- and nanoplastics (MNPs) have been detected in multiple organs and tissues, as well as human feces, urine, breastmilk, and neonatal meconium, suggesting widespread exposure and absorption. Larger MNPs are thought to be filtered out by normal bodily defenses, such as by mucus in the nose or by coughing. However, "ultrafine" particles are able to enter the circulatory system through the lungs. Additionally, when MNPs are introduced directly into the bloodstream, such as during medical treatment, they bypass our natural defenses. Although experimental studies within cell cultures and animals have shown possible biological effects, human evidence remains limited, and long-term health risks are still being researched.
Sources: en.wikipedia.org
=== Photobiont === The photobiont partner of Parmotrema perlatum is from Trebouxia, a green algal genus belonging to the order Trebouxiales (order Chlorophyta). It has been identified as an undescribed species within a clade containing Trebouxia arboricola. A study compared the desiccation tolerance and physiological responses of lichenised Trebouxia to isolated cultures of the same alga. Both forms can survive extended desiccation, but with differing responses to photo-oxidative stress. Lichenisation enhances the photoprotective mechanisms of Trebouxia, improving quenching of excess light energy, particularly under high relative humidity, and controlling reactive oxygen species production under light exposure. However, isolated cultures showed better photosynthetic performance after desiccation recovery. This research demonstrates the mutual benefits of the lichen-photobiont partnership, where the alga gains a sheltered environment boosting its resilience to environmental stressors. Further studies on Parmotrema perlatum revealed specific antioxidant mechanisms supporting its photobiont under stress. The lichen shows high levels of reactive oxygen species scavenging enzymes such as superoxide dismutase and ascorbate peroxidase, protecting the photobiont from oxidative damage during dehydration and rehydration cycles. This enhanced antioxidant system provides not only physical shelter but also biochemical protection, increasing the photobiont's resilience to environmental fluctuations.
== Veterinary uses == Prednisolone is used in the treatment of inflammatory and allergic conditions in cats, dogs, horses, small mammals such as ferrets, birds, and reptiles. Its usage in treating inflammation, immune-mediated disease, Addison's disease, and neoplasia is often considered off-label use. Many drugs are commonly prescribed for off-label use in veterinary medicine." Studies in ruminating species, such as alpacas, have shown that oral administration of the drug is associated with a reduced bioavailability compared to intravenous administration; however, levels that are therapeutic in other species can be achieved with oral administration in alpacas. It is used in a broad spectrum of diseases, for example, inflammation of scleral tissues, cornea, and conjunctiva in dogs. In horses, prednisolone acetate suspensions are priorly used to treat inflammation in the middle layer of the eye, also known as anterior uveitis and equine recurrent uveitis (ERU), which is the leading cause of visual impairment in horses. Prednisolone acetate eye drops are not to be used in other animals such as birds. Prednisolone acetate eye drops are also prescribed to dogs and cats to lessen swelling, redness, burning, and pain sensations after surgeries of the eye. Cats with conjunctivitis usually are required to avoid using ophthalmic preparations of corticosteroids and its derivatives. The most typical infections are caused by herpes virus.
== Harvesting and cultivation == The berries of A. chilensis are collected from wild plants from December to March of each year by families, mainly Mapuche, who collect their harvest near the Andes Mountains. The harvesting process involves collecting the side branches of trees, shaking them to separate the berries and leaves from the branches, and then employing a mechanical process to separate the berries from the leaves. In the Juan Fernandez Islands, the Juan Fernandez Women's Group has led efforts to reduce the presence of the species by encouraging local women to harvest to berries and create products for sale with them. The stored fruits are sold in local markets, with prices ranging from $6.5 to $15 per kilogram ($2.9 to $6.8/lb). The average area yield is about 220 kilograms (490 lb) per hectare annually, with an estimated yearly total of only 90 short tons (180,000 lb), due to remote access and difficulty of transportation. Aristotelia chilensis is planted in home gardens and is not grown on an orchard scale. Most of the fruits on the market have been gathered from the wild. Maqui is frost sensitive and fairly tolerant of seaside conditions. It prefers a well-drained soil in full sun, with some protection against cold, drying winds. The soil should be slightly acidic, with moderate fertility. Aristotelia chilensis can be planted in USDA zones 8 to 12. It is cultivated in Spain, and in milder, moister areas of Britain, where winter freezes cause dieback, thereby stimulating growth of more shoots in spring.
The advantages of supercritical fluid extraction (compared with liquid extraction) are that it is relatively rapid because of the low viscosities and high diffusivities associated with supercritical fluids. Alternative solvents to supercritical fluids may be poisonous, flammable or an environmental hazard to a much larger extent than water or carbon dioxide are. The extraction can be selective to some extent by controlling the density of the medium, and the extracted material is easily recovered by simply depressurizing, allowing the supercritical fluid to return to gas phase and evaporate leaving little or no solvent residues. Carbon dioxide is the most common supercritical solvent. It is used on a large scale for the decaffeination of green coffee beans, the extraction of hops for beer production, and the production of essential oils and pharmaceutical products from plants. A few laboratory test methods include the use of supercritical fluid extraction as an extraction method instead of using traditional solvents.
== Contraindications == Somapacitan should not be used in people with active malignancy, any stage of diabetic eye disease in which high blood sugar levels cause damage to blood vessels in the retina, acute critical illness, or those with acute respiratory failure, because of the increased risk of mortality with use of pharmacologic doses of somapacitan in critically ill individuals without growth hormone deficiency.
Sources: en.wikipedia.org
Influenced strongly by the white refugees who had fled south from the Congo, it presented chaotic doomsday scenarios of what black Rhodesian rule in Southern Rhodesia might mean, particularly for the white community. Proponents of the RF stand downplayed black Rhodesian grievances regarding land ownership and segregation, and argued that despite the racial imbalance in domestic politics—whites made up 5% of the population, but over 90% of registered voters—the electoral system was not racist as the franchise was based on financial and educational qualifications rather than ethnicity. They emphasised the colony's proud war record on Britain's behalf, and expressed a wish in the Cold War context to form an anti-communist, pro-Western front in Africa alongside South Africa and Portugal. These factors combined with what RF politicians and supporters saw as British decadence, chicanery and betrayal to create the case they put forward that UDI, while dubious legally and likely to provoke international uproar, might nevertheless be in their eyes justifiable and necessary for the good of the country and region if an accommodation could not be found with Whitehall.
Healthy centenarians are characterized by increased serum irisin levels, whereas levels of this hormone were found to be significantly lower in young patients with myocardial infarction. These findings may prompt further research into the role played by irisin not only in vascular disorders but also in life span modulation. Fibroblast growth factor 21 (FGF-21) production has been documented as a pathway to longevity. BAT activation through cold exposure up-regulates circulating fibroblast growth factor 21 (FGF21) in humans by 37%. FGF21 improves insulin sensitivity and glucose metabolism which may partially explain its longevity promoting benefits. Under basal environmental temperatures, HDAC3 primes expression of UCP1 and the brown fat thermogenic program to ensure acute cold survival through the deacetylation and activation of PGC-1alpha. Cold exposure increases SIRT1 phosphorylation/activity in both skeletal muscle and BAT, increasing thermogenesis and insulin sensitivity through deacetylation of PGC-1alpha and other protein targets. Elevated SIRT1 levels in people are associated with increased human longevity. SIRT1 (and the other sirtuins) have many metabolic effects, but an important one for improving health and longevity is the fact that SIRT1 increases insulin sensitivity and glucose control in skeletal muscles, triggers the browning of white fat and increases BAT activity.
In 2016, the US FDA used its authority under the Family Smoking Prevention and Tobacco Control Act to deem e-cigarette devices and e-liquids to be tobacco products, which meant it intended to regulate the marketing, labelling, and manufacture of devices and liquids; vape shops that mix e-liquids or make or modify devices were considered manufacturing sites that needed to register with US FDA and comply with good manufacturing practice regulation. E-cigarette and tobacco companies recruited lobbyists in an effort to prevent the US FDA from evaluating e-cigarette products or banning existing products already on the market. FDA testimony reported that legislation enacted in 2022 extended regulatory authority to nicotine from any source, including synthetic nicotine. In February 2014, the European Parliament passed regulations requiring standardization and quality control for liquids and vaporizers, disclosure of ingredients in liquids, and child-proofing and tamper-proofing for liquid packaging. In April 2014 the US FDA published proposed regulations for e-cigarettes. In the US some states tax e-cigarettes as tobacco products, and some state and regional governments have broadened their indoor smoking bans to include e-cigarettes. As of April 2017, 12 US states and 615 localities had prohibited the use of e-cigarettes in venues in which traditional cigarette smoking was prohibited. In 2015, at least 48 states and 2 territories had banned e-cigarette sales to minors.
According to the Syrian Observatory for Human Rights, the Ministry of Defense executed civilians at a poultry farm outside the town of Sahnaya. The SOHR stated that the Ministry of Defense ambushed Druze coming from Suwayda towards Sahnaya, resulting in 43 deaths. Some of the bodies were burned and others mutilated while the perpetrators (from the Ministry of Interior) reportedly chanted anti-Druze slogans.
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.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.