A practical reference on GABA-A receptor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-12-20 and is reviewed periodically as new material appears.
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.
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
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 |
|---|---|---|
| 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 |
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.
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 at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
=== Emergency gas supply === The professional diver is usually required to carry an emergency gas supply with sufficient gas to reach a place of safety in an emergency involving failure of the surface supplied gas. For surface oriented dives, this may require sufficient gas for planned decompression.
In fact, a swab-APPI-MS system designed for explosives and narcotics detection for security applications performs very well for all types of ambient analysis using a sampling wand and swab (right figure). A particular demonstration (unpublished) showed excellent sensitivity and specificity for detection of pesticide compounds on a variety of fruits and vegetables showing detection limits for 37 priority pesticides ranging from 0.02 to 3.0 ng well below safe limits.
=== Leak === On September 19, the Half-Life 2 source code was obtained by a German hacker, Axel Gembe, who had infiltrated Valve's internal network months earlier. According to Gembe, he shared it with another person, who leaked the code online in early October. Fans soon compiled a playable version of Half-Life 2, revealing how unfinished it was. The leaks damaged morale at Valve and slowed development. Fans also provided Valve with the details of people involved in the leaks. In March 2004, Gembe contacted Newell, saying he was a fan and had not acted maliciously. Newell worked with the FBI to invite Gembe to a fake job interview, planning to have him arrested in the United States; however, police arrested him in Germany. In November 2006, Gembe was sentenced to two years' probation. Valve implemented new policies to protect against leaks, such as requiring journalists to attend their office to play it before release.
The extreme lateral part of the ventromedial nucleus of the hypothalamus is responsible for the control of food intake. Stimulation of this area causes increased food intake. Bilateral lesion of this area causes complete cessation of food intake. Medial parts of the nucleus have a controlling effect on the lateral part. Bilateral lesion of the medial part of the ventromedial nucleus causes hyperphagia and obesity of the animal. Further lesion of the lateral part of the ventromedial nucleus in the same animal produces complete cessation of food intake. There are different hypotheses related to this regulation:
Sources: en.wikipedia.org
=== Neurosurgical research and innovations === Maroon has conducted extensive research into neurotrauma, brain tumors, and diseases of the spine, which led to many innovative techniques for diagnosing and treating these disorders. Maroon was the first to publish on the use of ultrasound to detect venous air emboli (1968). Maroon et al. were the first to publish on the use of ultrasound to detect air in patients during neurosurgical procedures (1969) and to assess ophthalmic artery reversal of flow, indicating a thrombosis of the carotid artery (1969). Maroon et al. published the simplified instrumentation for performing microvascular surgery in 1973, and in 1975, they pioneered the microsurgical approach to intra-orbital tumors. In 1977, they pioneered the use of CT scanning as a guidance system for performing intracranial biopsy. In the same year, Maroon published the first paper on "burning hands" syndrome related to sports-related spinal cord injuries in JAMA. In 1982, Maroon et al. pioneered the radical orbital decompression procedure for severe dysthyroid exophthalmos. In 1985, they were the first to compare microsurgical disc removal with chemonucleolysis and in 1986, they were the first to use a carbon dioxide laser in the management of lymphangiomas of the orbit. That year, Maroon et al. were among the first to describe their surgery outcomes with microlumbar discectomy. In 1987, Maroon and Onik introduced percutaneous automated discectomy as a new minimally invasive way to remove lumbar discs and subsequently published extensively on this technique.
The combination of these two steps, both of which are catalyzed by aminoacyl tRNA synthetase, produces a charged tRNA that is ready to add amino acids to the growing polypeptide chain. In addition to binding an amino acid, tRNA has a three nucleotide unit called an anticodon that base pairs with specific nucleotide triplets on the mRNA called codons; codons encode a specific amino acid. This interaction is possible thanks to the ribosome, which serves as the site for protein synthesis. The ribosome possesses three tRNA binding sites: the aminoacyl site (A site), the peptidyl site (P site), and the exit site (E site). There are numerous codons within an mRNA transcript, and it is very common for an amino acid to be specified by more than one codon; this phenomenon is called degeneracy. In all, there are 64 codons, 61 of each code for one of the 20 amino acids, while the remaining codons specify chain termination.
==== Heating ==== A report given to the Food and Drug Administration by the Institute of Food Technologists thoroughly discusses the thermal processing of food. A notable step in development of heat application to food processing is pasteurization, developed by Louis Pasteur in the nineteenth century. Pasteurization is used to kill microorganisms that could pose risks to consumers or shorten the shelf life of food products. Primarily applied to liquid food products, pasteurization is regularly applied to fruit juice, beer, milk, and ice cream. Heat applied during pasteurization varies from around 60 °C to kill bacteria to around 80 °C to kill yeasts. Most pasteurization processes have been optimized recently to involve several steps of heating at various temperatures and minimize the time needed for the process. A more severe food heating mechanism is thermal sterilization. While pasteurization destroys most bacteria and yeast growing in food products, the goal of sterilization is to kill almost all viable organisms found in food products including yeast, mold, bacteria, and spore forming organisms. Done properly, this process will greatly extend the shelf life of food products and can allow them to be stored at room temperature. As detailed in The Handbook of Food Preservation, thermal sterilization typically involves four steps. First, food products are heated to between 110 and 125 °C, and the products are given time for the heat to travel through the material completely.
Sources: en.wikipedia.org
=== Sanger sequencing-based decoding === Although many authors implicitly envisaged a traditional Sanger sequencing-based decoding, the number of codes to sequence simply according to the complexity of the library is definitely an unrealistic task for a traditional Sanger sequencing approach. Nevertheless, the implementation of Sanger sequencing for decoding DNA-encoded chemical libraries in high-throughput fashion was the first to be described. After selection and PCR amplification of the DNA-tags of the library compounds, concatamers containing multiple coding sequences were generated and ligated into a vector. Following Sanger sequencing of a representative number of the resulting colonies revealed the frequencies of the codes present in the DNA-encoded library sample before and after selection.
Microbats and a few megabats emit ultrasonic sounds to produce echoes. The sound intensity of these echoes is dependent on subglottic pressure. The bats' cricothyroid muscle, located inside the larynx, controls the orientation pulse frequency, which is an important function. By comparing the outgoing pulse with the returning echoes, bats can learn about their environment and detect prey in darkness. Some bat calls can reach over 140 decibels. Microbats use their larynx to emit echolocation signals through the mouth or the nose. Bat call frequencies range from as low as 11 kHz to as high as 212 kHz. The noses of various groups of bats have fleshy extensions, known as nose-leaves, which play a role in sound transmission. In low-duty cycle echolocation, bats can separate their calls and returning echoes by time. They have to time their short calls to finish before echoes return. In high-duty cycle echolocation, bats emit a continuous call and separate pulse and echo in frequency using the Doppler effect of their motion in flight. The shift of the returning echoes yields information relating to the motion and location of the bat's prey. These bats must deal with changes in the Doppler shift due to changes in their flight speed. They have adapted to change their pulse emission frequency in relation to their flight speed so echoes still return in the optimal hearing range. In addition to echolocating prey, bat ears are sensitive to sounds made by their prey, such as the fluttering of moth wings.
GeneReviews/NCBI/NIH/UW entry on Stickler Syndrome "Stickler Involved People". Stickler Involved People. Retrieved 2025-05-12. Patient group, now part of the Marfan Foundation "Stickler Syndrome UK". Stickler Syndrome UK. Retrieved 2025-05-12. British patient group
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.
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.