This is a working overview of elevated plus maze, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-04-17 and is reviewed periodically as new material appears.
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.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
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 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.
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.
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 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.
=== Historical evidence against balance of power theory === A 2021 assessment by Morten Skumsrud Andersen and William C. Wohlforth concluded that balance of power is not a universal empirical law and that it does not merit explanatory precedence in international relations research. In an attempt to disprove the balance of power theory, some realists have pointed to cases in international systems other than modern Europe where balancing failed and a hegemon arose. A collaboration between nine scholars (William Wohlforth, Richard Little, Stuart J. Kaufman, David Kang, Charles A. Jones, Victoria Tin-Bor Hui, Arthur Eckstein, Daniel Deudney, and William L. Brenner) pointed to the failure of state-like units to balance against Assyria in the first millennium BCE; the Hellenic successor states of Alexander the Great to balance against Rome; the Warring States to balance against the Qin dynasty in ancient China and five other cases. This cross-cultural research concludes:
=== Cyclic peptide binders Screening === Cyclic peptides can be successfully displayed on bacterial cell surface. By DNA randomization millions of cyclic peptides displayed on cell surface can be screened against a protein target using high-throughput FACS.
==== Macronutrient composition ==== The overall composition of the milk including the fat, protein, and lactose content is not altered substantially by the use of rBST in dairy cows. The milk may have a slight change in fat content within the first few weeks of rBST treatment as the cow is allowed to adjust her metabolism and feed intake. The changes in the fat content have been shown to be temporary. The composition of the milk has been examined in more than 200 different experiments. Natural variation within milk is normal with or without rBST treatment in cows due to genetics, location, feed, age, and other environmental factors. Protein in milk content has also been studied and was shown to have no apparent change in rBST treated cows. The vitamins and minerals that are normally in milk were also unaltered in milk from rBST treated cows. Freezing point, pH, thermal properties, and other manufacturing characteristics of milk were shown to be the same regardless of whether it came from rBST treated cows or not.
Sources: en.wikipedia.org
==== Psilocybin ==== Psilocybin has been shown in several studies to improve symptoms in people with treatment-resistant depression. In 2018 and 2019, the FDA designated psilocybin as a "breakthrough therapy" for drug-resistant depression and major depressive disorder.
== History == Turquoise was mined by pre-Columbian Native Americans in deposits in New Mexico (Los Cerrillos) and likely in California as well. Additionally, it was used by the Ancient Egyptians, although not very commonly. Several turquoise artefacts, such as beads and reclining calves, have also been found in Greece, dating to the Mycenaean era (1500BC). Turquoise mining later attracted brief European interest in the late 1800s. Prices peaked in 1890, then collapsed by 1912, ending large-scale operations. During Mohammad Khodabanda reign (1578–1587), accumulated turquoise dust from fifty years of mining in Safavid Iran was squandered lavishly, reflecting royal excess amid economic hardship, political discord, and rising factionalism among the qezelbash elite.
Under anoxic conditions, the predominant double-base lesion is a species in which C8 of guanine is linked to the 5-methyl group of an adjacent 3'-thymine (G[8,5- Me]T). Most of these oxygen-derived species are produced by normal aerobic metabolism. Normal cellular defense mechanisms destroy most of these. Repair of oxidative damages to DNA is frequent and ongoing, largely keeping up with newly induced damages. In rat urine, about 74,000 oxidative DNA adducts per cell are excreted daily. There is also a steady state level of oxidative damages in the DNA of a cell. There are about 24,000 oxidative DNA adducts per cell in young rats and 66,000 adducts per cell in old rats. Likewise, any damage to cells is constantly repaired. However, under the severe levels of oxidative stress that cause necrosis, the damage causes ATP depletion, preventing controlled apoptotic death and causing the cell to simply fall apart. Polyunsaturated fatty acids, particularly arachidonic acid and linoleic acid, are primary targets for free radical and singlet oxygen oxidations.
=== Pancreatic and thyroid safety === Historically, GLP-1 receptor agonists have carried warnings regarding acute pancreatitis and pancreatic cancer. However, large-scale cardiovascular outcome trials for semaglutide have not found a statistically significant increase in the incidence of these conditions in humans. The US prescription label contains a boxed warning for thyroid C-cell tumors. This warning is based on rodent studies; rodents possess a high density of GLP-1 receptors in their thyroid C-cells, which leads to hyperplasia and tumors when stimulated. In contrast, human thyroids express these receptors only marginally, making the risk of medullary thyroid carcinoma highly specific to rodents and clinically unlikely in humans. Semaglutide remains contraindicated in individuals with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2.
Sources: en.wikipedia.org
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.