If you have been reading about elevated plus maze 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 2025-10-24. 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.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
| 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 |
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.
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.
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.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
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.
=== Self-assembly === The self-assembly technique is used to generate peptide nanofibers and peptide amphiphiles. The method was inspired by the natural folding process of amino acid residues to form proteins with unique three-dimensional structures. The self-assembly process of peptide nanofibers involves various driving forces such as hydrophobic interactions, electrostatic forces, hydrogen bonding and van der Waals forces and is influenced by external conditions such as ionic strength and pH.
=== Repair phase === In the Repair phase, new tissue is generated which requires a balance of anti-inflammatory and pro-inflammatory eicosanoids. Anti-inflammatory eicosanoids include lipoxins, epi-lipoxins, and resolvins, which cause release of growth hormones.
Corneal cross-linking involves application of riboflavin solution to the eye that is activated by illumination with UV-A light for approximately 30 or fewer minutes. The riboflavin causes new bonds to form across adjacent collagen strands and proteoglycans in the stromal layer of the cornea, which recovers and preserves some of the cornea's mechanical strength. The corneal epithelial layer is generally removed to increase penetration of the riboflavin into the stroma, a procedure known as the Dresden protocol. People that are considered for treatment must undergo an extensive clinical workup, including corneal tomography, computerized corneal topography, endothelial microscopy, ultrasound pachymetry, b-scan sonography, keratometry and biomicroscopy.
Often this irregular shape is due to their many centers of ossification or because they contain bony sinuses. The bones of the spine, pelvis, and some bones of the skull are irregular bones. Examples include the ethmoid and sphenoid bones.
The main nuclear power source in a reactor is the neutron-induced fission of a nuclide; the synthetic fissile nuclei 233U and 239Pu can be bred from neutron capture by the naturally occurring quantity nuclides 232Th and 238U. 235U occurs naturally in significant amounts and is also fissile. In the thorium fuel cycle, the fertile isotope 232Th is bombarded by slow neutrons, undergoing neutron capture to become 233Th, which undergoes two consecutive beta decays to become first 233Pa and then the fissile 233U:
Sources: en.wikipedia.org
=== Violent Crime and Law Enforcement Act === Clinton signed the 1994 Crime Bill, which was written by Senator Joe Biden of Delaware. It included 30 billion dollars' worth of federal anticrime funding. Specific to the war on drugs, Clinton included the three-strikes law, which required a mandatory life sentence for any felony violent crime conviction after two other prior convictions. Some social justice critics argue that the law disproportionately affected criminals in urban neighborhoods hurt by policing the war on drugs, rather than white-collar criminals. The bill also authorized $16 million in new funding for the development of federal prisons and state and local police forces. The Justice Policy Institute stated in 2008 that the administration's "tough on crime" policies caused larger increases in federal and state inmate populations than for any other president in American history. The act also saw the expansion of the federal death penalty. Sixty new capital punishment charges were created including non-homicidal narcotics offenses, drive-by shootings resulting in death, and carjackings relating to death. Between 1994 and 1999, nearly two thirds of people sentenced to the federal death penalty were black during Clinton's presidency, nearly seven times that of their representation in the US population. During his two terms, the federal prison population increased from 1.3 million to 2 million inmates. The law featured a provision that removed the approval of Pell Grants for low-income inmates in federal prison.
(2026) interpret the morphological variation of Middle Stone Age human mandibles from the Klasies River Main Site (South Africa) as not conclusively indicative of presence of more than one population lineage. García-Morato et al. (2026) reconstruct climate and vegetation changes in southern Africa from Marine Isotope Stage 5 to Marine Isotope Stage 3, and find that the emergence of the 76,000-67,000-years-old Stilbaai lithic technocomplex coincided with humid, cool phase that likely supported high biomass and expanded habitable zones, while the 64,000-60,000 years of Howiesons Poort technocomplex arose and ended during peaks of aridity, with a wetter interval midway through them. Evidence from the study of engraved ostrich eggshell fragments from the Howiesons Poort technocomplex, indicating that the studied engravings represent an expression of complex graphic representation by Middle Stone Age humans, is presented by Decembrini et al. (2026). Alichane et al. (2026) study the morphology of the enamel-dentine junction of the first and second molars in hominins associated with the Middle Stone Age Aterian technocomplexes in northwestern Africa, reporting evidence of overall closer morphological similarity to anatomically modern humans than to Neanderthals, but also evidence of morphological differences that might be related to the age and large size of the studied teeth.
== Presentation == People presenting with possible auricular hematoma often have additional injuries (for example, head/neck lacerations) due to the frequently traumatic causes of auricular hematoma. The ear itself is often tense, fluctuant, and tender with throbbing pain. However, because of potentially more remarkable injuries often associated with auricular hematoma, it can easily be overlooked without directed attention.
=== Other antifreezes === Propylene glycol methyl ether is used as an antifreeze in diesel engines. It is more volatile than glycol. Once used for automotive antifreeze, glycerol has the advantage of being non-toxic, withstands relatively high temperatures, and is noncorrosive. It is not however used widely. Glycerol was historically used as an antifreeze for automotive applications before being replaced by ethylene glycol. Volkswagen introduced G13 (TL 774-G) antifreezes containing glycerol in 2008, marketed as better for the environment due to its low toxicity and reduced CO2 emissions. However, since 2018, they have moved on to G12EVO (TL 774-L) which no longer contains glycerol. Glycerol is mandated for use as an antifreeze in many sprinkler systems.
Genetic code is a set of rules used by living cells to translate information encoded within genetic material (DNA or RNA sequences of nucleotide triplets or codons) into proteins. Translation is accomplished by the ribosome, which links proteinogenic amino acids in an order specified by messenger RNA (mRNA), using transfer RNA (tRNA) molecules to carry amino acids and to read the mRNA three nucleotides at a time. The genetic code is highly similar among all organisms and can be expressed in a simple table with 64 entries. The codons specify which amino acid will be added next during protein biosynthesis. With some exceptions, a three-nucleotide codon in a nucleic acid sequence specifies a single amino acid. The vast majority of genes are encoded with a single scheme (see the RNA codon table). That scheme is often called the canonical or standard genetic code, or simply the genetic code, though variant codes (such as in mitochondria) exist.
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.
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.