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 2025-12-08 and is reviewed periodically as new material appears.
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.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
| Property | Value | Notes |
|---|---|---|
| Primary route studied | Intranasal | Also examined parenterally in animal work |
| Reported plasma half-life | Minutes to tens of minutes | Values vary widely between reports |
| Main model systems | Rodent behavioural and cell assays | Human trials are few and small |
| Principal proposed targets | GABA-A receptor, GABA transaminase | Monoamine and neurotrophic pathways also reported |
| Evidence grade | Preliminary | Limited independent replication |
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.
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.
(2026) make the name of the toxodontid Andinotoxodon bolivarensis, originally described in a doctoral dissertation, available under the International Code of Zoological Nomenclature. The first confirmed fossil material of Late Pleistocene Toxodon platensis from the San Luis Province (Argentina), providing information on the intracranial anatomy of members of this species, is described from the Barranquita Formation by Hernández Del Pino et al. (2026). Evidence from the study of tooth wear of Tremacyllus and Paedotherium, interpreted as indicating that pachyrukhine hegetotheriid notoungulates were mainly fruit-seed consumers rather than grazers, is presented by Armella & Croft (2026). A study on the evolution of the morphological similarity to molar teeth in premolar teeth of ungulates, based on data from extant and extinct artiodactyls and perissodactyls, is published by Ashbaugh, Jamniczky & Theodor (2026). A study on tooth wear of early Pleistocene ungulates from the Quibas site (Murcia, Spain), interpreted as indicative of a broad spectrum of feeding behaviours consistent with presence of mosaic environments including grasslands with wooded patches, is published by Ramírez-Pedraza, Agustí & Piñero (2026). Hussain et al. (2026) reconstruct the dietary presences of Pleistocene ungulates from the Pinjor Formation (Pakistan) on the basis of the study of their tooth wear, interpreted as indicating that the studied assemblage was dominated by grazers but also included browsers and mixed-feeders.
Cauliflower ear is an irreversible condition that occurs when the external portion of the ear is hit and develops a blood clot or other collection of fluid under the perichondrium. This separates the cartilage from the overlying perichondrium that supplies its nutrients, causing it to die and resulting in the formation of fibrous tissue in the overlying skin. As a result, the outer ear becomes permanently swollen and deformed, resembling a cauliflower, hence the name. The condition is common in sport wrestling, professional wrestling, boxing, and kickboxing, in martial arts such as Brazilian jiu-jitsu, judo, sumo, and mixed martial arts, and in full-contact sports such as rugby union and rugby league.
Depending on the solute and range of concentration, an aqueous electrolyte solution can have either a larger or smaller viscosity compared with pure water at the same temperature and pressure. For instance, a 20% saline (sodium chloride) solution has viscosity over 1.5 times that of pure water, whereas a 20% potassium iodide solution has viscosity about 0.91 times that of pure water. An idealized model of dilute electrolytic solutions leads to the following prediction for the viscosity
Some non-α-amino acids exist in organisms. In these structures, the amine group is displaced further from the carboxylic acid end of the amino acid molecule. Thus a β-amino acid has the amine group bonded to the second carbon away, and a γ-amino acid has it on the third. Examples include β-alanine, GABA, and δ-aminolevulinic acid.
Sources: en.wikipedia.org
== Veterinary uses == Phenobarbital is one of the first-line drugs of choice to treat epilepsy in dogs, as well as cats. It is also used to treat feline hyperesthesia syndrome in cats when anti-obsessional therapies prove ineffective. It may also be used to treat seizures in horses when benzodiazepine treatment has failed or is contraindicated.
== Young adults == By far, the most common cause of severe hypoglycemia in this age range is insulin injected for type 1 diabetes. Circumstances should provide clues fairly quickly for the new diseases causing severe hypoglycemia. All of the congenital metabolic defects, congenital forms of hyperinsulinism, and congenital hypopituitarism are likely to have already been diagnosed or are unlikely to start causing new hypoglycemia at this age. Body mass is large enough to make starvation hypoglycemia and idiopathic ketotic hypoglycemia quite uncommon. Recurrent mild hypoglycemia may fit a reactive hypoglycemia pattern, but this is also the peak age for idiopathic postprandial syndrome, and recurrent "spells" in this age group can be traced to orthostatic hypotension or hyperventilation as often as demonstrable hypoglycemia.
In August 2010, James Brokenshire, the Home Office drugs minister, announced plans to create a new category in the Misuse of Drugs Act, through the Police Reform and Social Responsibility Bill, that would allow new legal highs to be made temporarily illegal, without the need for a vote in parliament or advice from the ACMD, as was required to categorise mephedrone. According to the Independent Scientific Committee on Drugs, after mephedrone was made illegal, a street trade in the drug emerged, with prices around double those prior to the ban, at £20–£25 per gram. In September 2010, Druglink reported the ban had a mixed effect on mephedrone use, with it decreasing in some areas, remaining similar in others, and becoming more prevalent in some areas. In an online survey of 150 users after the ban, 63% said they were continuing to use mephedrone; of those, half claimed unchanged usage amounts (as to dosage and frequency), and half claimed decreased usage. Compared to previous surveys, more users purchased it from dealers, rather than the internet. The average price per gram was £16, compared to around £10 before the ban. The 2010 Mixmag survey of 2,500 nightclubbers found one quarter had used mephedrone in the previous month, the price had roughly doubled since it was made illegal, and it was more likely to be cut with other substances. Of those who had already used mephedrone prior to the ban, 75% had continued to use it after the ban. Of the various drugs used by the survey participants, users were more likely to have concerns about it.
Sources: en.wikipedia.org
The Mystery of the Yellow Room by Leroux opened 14 February 1912 in Paris, and a translation by Hannaford Bennett played 93 performances at the St James Theatre in London in 1920. Sybil Thorndike played Mathilde. Film and TV:
== Drugs withdrawn == The following therapeutic drugs were withdrawn from the market primarily because of hepatotoxicity: Troglitazone, bromfenac, trovafloxacin, ebrotidine, nimesulide, nefazodone, ximelagatran and pemoline.
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula −OH and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy groups. Both the negatively charged anion HO−, called hydroxide, and the neutral radical HO·, known as the hydroxyl radical, consist of an unbonded hydroxy group. According to IUPAC definitions, the term hydroxyl refers to the hydroxyl radical (·OH) only, while the functional group −OH is called a hydroxy group.
The E1 subunit, called the pyruvate dehydrogenase subunit, is either a homodimer (comprising two "α" chains, e.g. in Escherichia coli) or a heterotetramer of two different chains (two "α" and two "β" chains). A magnesium ion forms a 4-coordinate complex with three, polar amino acid residues (Asp, Asn, and Tyr) located on the alpha chain, and the thiamine diphosphate (TPP) cofactor directly involved in decarboxylation of the pyruvate.
Sources: en.wikipedia.org
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.
The peptide enters plasma rapidly and is broken down by ordinary proteases into amino acids and shorter fragments. Reported half-lives are short. Whether meaningful amounts of the intact molecule reach the brain is an open question.
Most clinical reports are small, published in Russian and not independently replicated. English-language reviews highlight the absence of large randomised trials. Conclusions about efficacy should be treated as provisional.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.