If you have been reading about BDNF and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-10-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Principal proposed target | GABA-A receptor complex | Hypothesis derived mainly from animal pharmacology |
| Common behavioral assay | Elevated plus maze | Rodent test for anxiety-like behavior |
| Reported molecular marker | Hippocampal BDNF expression | Measured by immunoassay or mRNA quantification |
| Typical dosing route | Intranasal | Chosen to reduce first-pass metabolism |
| Reported plasma half-life | Minutes | Based on limited peptide stability data |
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.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
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.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Films generate income from several revenue streams, including theatrical exhibition, home video, television broadcast rights, and merchandising. However, theatrical box-office earnings are the primary metric for trade publications in assessing the success of a film, mostly because of the availability of the data compared to sales figures for home video and broadcast rights, but also because of historical practice. Included on the list are charts of the top box-office earners (ranked by both the nominal and real value of their revenue), a chart of high-grossing films by calendar year, a timeline showing the transition of the highest-grossing film record, and a chart of the highest-grossing film franchises and series. All charts are ranked by international theatrical box-office performance where possible, excluding income derived from home video, broadcasting rights, and merchandise. Traditionally, war films, musicals, and historical dramas have been the most popular genres, but franchise films have been among the best performers of the 21st century. There is strong interest in the superhero genre, with eleven films in the Marvel Cinematic Universe featuring among the nominal top-earners. The most successful superhero film, Avengers: Endgame, is also the second-highest-grossing film on the nominal earnings chart, and there are four films in total based on the Avengers comic books charting in the top twenty-five.
== G == G protein - G protein-coupled receptor - G3P - GABA - GABA receptor - GABA-A receptor - gag-onc fusion protein - galanin - gamete - gamma-chain immunoglobulin - gamma-delta T-cell antigen receptor - gastrin - gastrointestinal hormone receptor - gastrula - gel electrophoresis - gene - gene expression - gene pool - gene regulatory network - genetic carrier - genetic code - genetic drift - genetic engineering - genetic fingerprint - genetic recombination - genetics - genome - genomics - genotype - glial fibrillary acidic protein - globin - glucagon - glucagon receptor - glucocorticoid receptor - glucose - glutamate - glutamate receptor - glutamic acid - glutamine - glycerine - glycine - glycine receptor - glycolipid - glycolysis - glycoprotein - gonadorelin - gradient - granulocyte colony-stimulating factor - granulocyte colony-stimulating factor receptor - granulocyte-macrophage colony-stimulating factor - granulocyte-macrophage colony-stimulating factor receptor - granzyme - growth factor receptor - GTP-binding protein - GTPase
==== Receptor and ion channel targets ==== Caffeine is an antagonist of adenosine A2A receptors, and knockout mouse studies have specifically implicated antagonism of the A2A receptor as responsible for the wakefulness-promoting effects of caffeine. Antagonism of A2A receptors in the ventrolateral preoptic area (VLPO) reduces inhibitory GABA neurotransmission to the tuberomammillary nucleus, a histaminergic projection nucleus that activation-dependently promotes arousal. This disinhibition of the tuberomammillary nucleus is the downstream mechanism by which caffeine produces wakefulness-promoting effects. Caffeine is an antagonist of all four adenosine receptor subtypes (A1, A2A, A2B, and A3), although with varying potencies. The affinity (KD) values of caffeine for the human adenosine receptors are 12 μM at A1, 2.4 μM at A2A, 13 μM at A2B, and 80 μM at A3. Antagonism of adenosine receptors by caffeine also stimulates the medullary vagal, vasomotor, and respiratory centers, which increases respiratory rate, reduces heart rate, and constricts blood vessels. Adenosine receptor antagonism also promotes neurotransmitter release (e.g., monoamines and acetylcholine), which endows caffeine with its stimulant effects; adenosine acts as an inhibitory neurotransmitter that suppresses activity in the central nervous system. Heart palpitations are caused by blockade of the A1 receptor. Because caffeine is both water- and lipid-soluble, it readily crosses the blood–brain barrier that separates the bloodstream from the interior of the brain.
== Medical uses == Venlafaxine is used primarily for the treatment of depression, general anxiety disorder, social phobia, panic disorder, and vasomotor symptoms. Concerns that noradrenergic reuptake might precipitate anxiety have not been borne out in randomized trials: a 2016 systematic review of 52 double-blind, placebo-controlled studies (mostly with venlafaxine or duloxetine) found clinically significant improvements in anxiety symptoms and no signal for treatment-emergent anxiety attributable to SNRIs. Venlafaxine has been used off label for the treatment of diabetic neuropathy and migraine prevention. It may work on pain via effects on the opioid receptor. It has also been found to reduce the severity of 'hot flashes' in menopausal women and men on hormonal therapy for the treatment of prostate cancer. Due to its action on both the serotonergic and adrenergic systems, venlafaxine is also used as a treatment to reduce episodes of cataplexy, a form of muscle weakness, in patients with the sleep disorder narcolepsy. Some open-label and three double-blind studies have suggested the efficacy of venlafaxine in the treatment of attention deficit-hyperactivity disorder (ADHD). Clinical trials have found possible efficacy in those with post-traumatic stress disorder (PTSD). Case reports, open trials and blinded comparisons with established medications have suggested the efficacy of venlafaxine in the treatment of obsessive–compulsive disorder.
== External links == Clinical trial number NCT00001262 for "Copper Histidine Therapy for Menkes Diseases" at ClinicalTrials.gov Clinical trial number NCT00811785 for "Molecular Bases of Response to Copper Treatment in Menkes Disease, Related Phenotypes, and Unexplained Copper Deficiency" at ClinicalTrials.gov
Sources: en.wikipedia.org
==== Reactions of cysteines ==== Because free cysteine rarely occurs on protein surface, it is an excellent choice for chemoselective modification. Under basic condition, the cysteine residues will be deprotonated to generate a thiolate nucleophile, which will react with soft electrophiles, such as maleimides and iodoacetamides (shown in the first two reactions in Figure 2 below). As a result, a carbon-sulfur bond is formed. Another modification of cysteine residues involves the formation of disulfide bond (shown in the third reaction in Figure 2). The reduced cysteine residues react with exogenous disulfides, generating new a disulfide bond on the protein. An excess of disulfides is often used to drive the reaction, such as 2-thiopyridone and 3-carboxy-4-nitrothiophenol. Electron-deficient alkynes were demonstrated to selectively react with cysteine residues of proteins in the presence of other nucleophilic amino acid residues. Depending on the alkyne substitution, these reactions can produce either cleavable (when alkynone derivatives are used), or hydrolytically stable bioconjugates (when 3-arylpropiolonitriles are used; the last reaction below in Figure 2).
=== Board game === Main articles: Le Havre (board game) Le Havre is a board game about the development of the town of Le Havre. It was inspired by the games Caylus and Agricola and was developed in December 2007.
=== Other === Other causes of dwarfism are spondyloepiphyseal dysplasia congenita, diastrophic dysplasia, pseudoachondroplasia, hypochondroplasia, Noonan syndrome, primordial dwarfism, Cockayne syndrome, Kniest dysplasia, Turner syndrome, osteogenesis imperfecta (OI), and hypothyroidism. Severe shortness with skeletal distortion also occurs in several of the mucopolysaccharidoses and other storage disorders. Hypogonadotropic hypogonadism may cause proportionate, yet temporary, dwarfism. NPR2 disproportionate dwarfism was discovered recently and is caused by a mutant gene.
{\displaystyle \mathrm {Purity} ={\frac {w_{\mathrm {std} }\times n[\mathrm {H} ]_{\mathrm {std} }\times MW_{\mathrm {spl} }}{w_{\mathrm {spl} }\times MW_{\mathrm {std} }\times n[\mathrm {H} ]_{\mathrm {spl} }}}\times P}
Sources: en.wikipedia.org
They further added that the airstrikes destroyed two corps headquarters, three brigade headquarters, two ammunition depots, one logistics base, three battalion headquarters, two sector headquarters, and more than 80 tanks, artillery pieces, and APCs (armoured personnel carriers). Pakistani officials also said that 27 border posts held by Taliban forces were destroyed and nine were captured. Taliban spokesperson Zabihullah Mujahid confirmed airstrikes in Kabul, Kandahar, Paktia, and several other locations, and stated that these airstrikes did not cause any casualties. The Taliban spokesperson also announced on X (formerly Twitter) that Taliban forces had responded to the airstrikes with attacks against Pakistani military positions in Kandahar and Helmand, two provinces in Afghanistan, although the post was later deleted. In Kabul, residents reported that airstrikes struck an ammunition depot near Darulaman, triggering hours of secondary explosions that rattled homes across the capital. Residents also reported hearing the sound of many ambulance sirens following the airstrike on the ammunition depot. Satellite images reviewed by The New York Times (NYT) confirmed an airstrike on an ammunition depot in Kabul. Additionally, satellite imagery released by Planet Labs revealed damage at two locations in Kabul, which are 400 meters apart. In Gardez, scorch marks and damage to four buildings at a military base belonging to Taliban forces were visible from satellite imagery.
The clitoral body (also known as the shaft of the clitoris) is a portion behind the glans that contains the union of the corpora cavernosa, a pair of sponge-like regions of erectile tissue that hold most of the blood in the clitoris during erection. It is homologous to the penile shaft in the male. The two corpora forming the clitoral body are surrounded by thick fibro-elastic tunica albuginea, a sheath of connective tissue. These corpora are separated incompletely from each other in the midline by a fibrous pectiniform septum – a comblike band of connective tissue extending between the corpora cavernosa. The clitoral body is also connected to the pubic symphysis by the suspensory ligament. The body of the clitoris is a bent shape, which makes the clitoral angle or elbow. The angle divides the body into the ascending part (internal) near the pubic symphysis and the descending part (external), which can be seen and felt through the clitoral hood.
==== Dextromethorphan ==== Dextromethorphan/bupropion, sold under the brand name Auvelity, is a combination medication approved by the US FDA in 2022 for the treatment of major depressive disorder (MDD) in adults. The formulation pairs dextromethorphan, an N-methyl-D-aspartate (NMDA) receptor antagonist and sigma-1 receptor agonist, with bupropion, a norepinephrine-dopamine reuptake inhibitor that also functions as a CYP2D6 enzyme inhibitor. Bupropion is included in the combination to slow the metabolism of dextromethorphan by inhibiting CYP2D6, thereby increasing its bioavailability and allowing dextromethorphan's potential antidepressant effects to be achieved. While the precise mechanism of action in treating depression is not fully understood, it is hypothesized that the medication works by modulating glutamate signaling and influencing other neurotransmitter systems.
Sources: en.wikipedia.org
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.
Behavioral endpoints include time spent in open arms of the elevated plus maze and avoidance latencies. Biochemical endpoints include BDNF concentration, cytokine levels, and monoamine metabolite ratios in brain tissue.
Most published studies are small, originate from a limited number of laboratories, and lack independent replication. Dose-response relationships, measured brain exposure, and long-term outcomes are not well characterized.
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.