Neurotrophic factor 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.
Updated 2026-06-25. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
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.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
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.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
=== 2009–2013: Time Machine Tour and Clockwork Angels === On February 16, 2009, Lifeson remarked that the band might begin working on a new album in the fall of 2009, with Nick Raskulinecz again producing. In November 2009, Lee, Lifeson and Peart were awarded the International Achievement Award at the annual SOCAN Awards in Toronto. On March 19, 2010, the CBC posted a video interview with Lee and Lifeson in which they discussed Rush's induction into the Canadian Songwriters Hall of Fame on March 28, 2010, at the Toronto Centre for the Arts' George Weston Recital Hall. The band was recognized for the songs "Limelight", "Closer to the Heart", "The Spirit of Radio", "Tom Sawyer" and "Subdivisions". In addition to discussing their induction, Lee and Lifeson touched on future material, with Lee saying, "Just about a month and a half ago we had no songs. And now we've been writing, and now we've got about 6 songs that we just love..." On March 26, 2010, in an interview with The Globe and Mail, Lifeson remarked that there was even the potential for two supporting tours. Soon afterwards, Peart confirmed that Raskulinecz had returned as co-producer. In April 2010, Rush recorded "Caravan" and "BU2B", two new songs to be featured on the band's then-upcoming studio album Clockwork Angels, at Blackbird Studios in Nashville with Raskulinecz. "Caravan" and "BU2B" were released together on June 1, 2010, and made available for digital download.
252.01 Hyperparathyroidism, primary 252.1 Hypoparathyroidism 253 Disorders of the pituitary gland and its hypothalamic control 253.3 Growth hormone deficiency 253.6 SIADH 254 Diseases of thymus gland 255 Disorders of adrenal glands 255.0 Cushing's syndrome 256 Ovarian dysfunction 256.2 Ovarian failure, postablative 256.39 Ovarian failure, other 256.4 Ovaries, polycystic 257 Testicular dysfunction 257.2 Testicular hypofunction 258 Polyglandular dysfunction and related disorders 259 Other endocrine disorders 259.0 Puberty, delayed 259.1 Sexual precocity
In Germany, dihydrocodeine has been used off-label in OAT for many years, however it is no longer frequently prescribed for this purpose. Extended-release dihydrocodeine is again in current use in Austria for this reason. Research into the usefulness of piritramide, extended-release hydromorphone (including polymer implants lasting up to 90 days), dihydroetorphine and other substances for OAT is at various stages in a number of countries. In 2020 in Vancouver, Canada, health authorities began vending machine dispensing of hydromorphone tablets as a response to elevated rates of fatal overdose from street drugs contaminated with fentanyl and fentanyl analogues. In some countries (not the US, UK, Canada, or Australia), regulations enforce a limited time period for people on OAT/OST programs that conclude when a stable economic and psychosocial situation is achieved. (Patients with HIV/AIDS or hepatitis C are usually excluded from this requirement.) In practice, 40–65% of patients maintain complete abstinence from opioids while receiving opioid agonist therapy, and 70–95% are able to reduce their use significantly, while experiencing a concurrent elimination or reduction in medical (improper diluents, non-sterile injecting equipment), psychosocial (mental health, relationships), and legal (arrest and imprisonment) issues that can arise from the use of illicit opioids. OAT/OST outlets in some settings also offer basic primary health care.
Sources: en.wikipedia.org
1993/2589) Mental Health Services of Salford National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2590) Hartlepool Community Care National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2591) Blackburn, Hyndburn and Ribble Valley Health Care National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2592) Northumberland Community Health National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2593) North Manchester Healthcare National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2594) Community Healthcare Bolton National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2595) CommuniCare National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2596) Blackpool, Wyre and Fylde Community Health Services National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2597) Blackpool Victoria Hospital National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2598) Bury Health Care National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2599)
== Biological properties == Ionophores are widely used in cell physiology experiments and biotechnology as these compounds can effectively perturb gradients of ions across biological membranes and thus they can modulate or enhance the role of key ions in the cell. Many ionophores have shown antibacterial and antifungal activities. Some of them also act against insects, pests and parasites. Some ionophores have been introduced into medicinal products for dermatological and veterinary use. A large amount of research has been directed toward investigating novel antiviral, anti-inflammatory, anti-tumor, antioxidant and neuroprotective properties of different ionophores. Chloroquine is an antimalarial and antiamebic drug. It is also used in the management of rheumatoid arthritis and lupus erythematosus. Pyrithione is used as an anti-dandruff agent in medicated shampoos for seborrheic dermatitis. It also serves as an anti-fouling agent in paints to cover and protect surfaces against mildew and algae. Clioquinol and PBT2 are 8-hydroxyquinoline derivatives. Clioquinol has antiprotozoal and topical antifungal properties, however its use as an antiprotozoal agent has widely restricted because of neurotoxic concerns. Clioquinol and PBT2 are currently being studied for neurodegenerative diseases, such as Alzheimer's disease, Huntington's disease and Parkinson's disease. Gramicidin is used in throat lozenges and has been used to treat infected wounds. Epigallocatechin gallate is used in many dietary supplements and has shown slight cholesterol-lowering effects.
Natriuretic peptide receptor B (NPR2), also known as atrionatriuretic peptide receptor B and formerly as guanylate cyclase B, is an atrial natriuretic peptide receptor which in humans is encoded by the NPR2 gene. A mutation in the NPR2 gene can result in achondroplasia and disproportionate dwarfism with short limbs.
Sources: en.wikipedia.org
== Determination of Beta Turns == Beta turns are another type of “short” or local secondary structure that is distinct from the more common helices, beta sheets or random coils. Beta turns are reasonably abundant (15%) and very important secondary structures in proteins. In particular, beta turns play a critical role in defining the topology of proteins. They also likely play a role in initiating early packing events during the protein folding process. In VADAR beta turns are identified under the BTURN header using standard Roman numeral notation (I = type I, II = type II, etc.). In VADAR, beta turns are identified using a combination of different pieces of information including hydrogen bond data, the location of previously identified secondary structures and the value of their local dihedral angles. In VADAR the classification and nomenclature used for beta turns follows the definitions proposed by Wilmot and Thornton.
Tracheal agenesis is a rare birth defect in which the trachea fails to develop. The defect is usually fatal though sometimes surgical intervention has been successful. A tracheoesophageal fistula is a congenital defect in which the trachea and esophagus are abnormally connected (a fistula). This is because of abnormalities in the separation between the trachea and oesophagus during development. This occurs in approximately 1 in 3,000 births, and the most common abnormalities is a separation of the upper and lower ends of the oesophagus, with the upper end finishing in a closed pouch. Other abnormalities may be associated with this, including cardiac abnormalities, or VACTERL syndrome. Such fistulas may be detected before a baby is born because of excess amniotic fluid; after birth, they are often associated with pneumonitis and pneumonia because of aspiration of food contents. Congenital fistulas are often treated by surgical repair. In adults, fistulas may occur because of erosion into the trachea from nearby malignant tumours, which erode into both the trachea and the oesophagus. Initially, these often result in coughing from swallowed contents of the oesophagus that are aspirated through the trachea, often progressing to fatal pneumonia; there is rarely a curative treatment. A tracheo-oesophageal puncture is a surgically created hole between the trachea and the esophagus in a person who has had their larynx removed. Air travels upwards from the surgical connection to the upper oesophagus and the pharynx, creating vibrations that create sound that can be used for speech.
== Pharmacology == It selectively binds to inflamed tissues (Prostaglandin synthetase inhibitor) and is normally free of adverse systemic effects. Unlike other NSAIDs, it does not inhibit cyclooxygenase or lipooxygenase, and is not ulcerogenic. Benzydamine has been investigated for activity at several ion channels and receptors involved in nociception. In vitro electrophysiological studies have shown that it inhibits voltage-gated sodium channel Nav1.8 currents at micromolar concentrations, while having no action as an agonist or antagonist at TRPA1 or TRPV1 channels, and no significant effect on Kv7.2/7.3 potassium channels. It is described as having powerful reinforcing effects in animals and showing cross-sensitization with drugs of misuse such as heroin and cocaine. It is hypothesized that it has cannabinoid agonistic activity and this may account for its recreational and hallucinogenic effects. However, it has also been theorized that, based on structural similarity to lysergic acid diethylamide (LSD) and descriptions of its visual hallucinatory effects, benzydamine might be acting as a serotonin 5-HT2A receptor agonist and hence as a serotonergic psychedelic. More research is needed to determine the mechanism of action of the effects of benzydamine as a drug of misuse.
=== Federal funding === Canada's National Research Council (NRC) provided Providence Therapeutics with CAD$5 million for the launch of January 2021 first phase of PTX-COVID19-B clinical trials. As part of the federal government's "next generation manufacturing supercluster" program, Providence and Northern mRNA had also been "cleared to access up to $5 million" towards the manufacturing start up process, according to a federal government spokesperson. The CBC report in late April 2021 also stated that "it could be eligible for a slice of $113 million in additional funding from the National Research Council of Canada Industrial Research Assistance Program". The federal government had provided funding to some other companies in Canada that were also working to develop a COVID-19 vaccine. Sorenson as Providence Therapeutics CEO posted an open letter to Prime Minister Justin Trudeau, in which he requested $CDN 150 million upfront to be used to pay for clinical trial and material costs. On April 29, 2021, Sorenson appeared before the House of Commons standing committee on international trade, to ask the Minister of Procurement, Anita Anand, to consider PTX-COVID19-B as an alternative to Moderna and Pfizer for the "2022 booster vaccines". Sorenson said that the NRC had approached Providence Therapeutics in 2020 after the company had announced their Phase I trial PTX-COVID19-B. Sorenson told the Standing Committee that, "We've had really good dialogue ever since phase I started. That process has gone on.
Sources: en.wikipedia.org
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.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
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.