This is a working overview of electrospray ionization, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-10-01. Anything still debated is marked as such rather than presented as settled.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
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.
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.
=== Binary, charge-neutral === Group 2 elements calcium, strontium, and barium can all form octacarbonyl complexes M(CO)8 (M = Ca Sr, Ba). The compounds were characterized in cryogenic matrices by vibrational spectroscopy and in gas phase by mass spectrometry. Group 4 elements with 4 valence electrons are expected to form heptacarbonyls; while these are extremely rare, substituted derivatives of Ti(CO)7 are known. Group 5 elements with 5 valence electrons, again are subject to steric effects that prevent the formation of M–M bonded species such as V2(CO)12, which is unknown. The 17-VE V(CO)6 is however well known. Group 6 elements with 6 valence electrons form hexacarbonyls Cr(CO)6, Mo(CO)6, W(CO)6, and Sg(CO)6. Group 6 elements (as well as group 7) are also well known for exhibiting the cis effect (the labilization of CO in the cis position) in organometallic synthesis. Group 7 elements with 7 valence electrons form pentacarbonyl dimers Mn2(CO)10, Tc2(CO)10, and Re2(CO)10. Group 8 elements with 8 valence electrons form pentacarbonyls Fe(CO)5, Ru(CO)5 and Os(CO)5. The heavier two members are unstable, tending to decarbonylate to give Ru3(CO)12, and Os3(CO)12. The two other principal iron carbonyls are Fe3(CO)12 and Fe2(CO)9. Group 9 elements with 9 valence electrons and are expected to form tetracarbonyl dimers M2(CO)8. In fact the cobalt derivative of this octacarbonyl is the only stable member, but all three tetramers are well known: Co4(CO)12, Rh4(CO)12, Rh6(CO)16, and Ir4(CO)12.
3-Hydroxyeticyclidine (3-HO-PCE) is a novel dissociative drug of the arylcyclohexylamine class, related to phencyclidine. It was first identified as a novel psychoactive substance in Sweden in 2017, and has subsequently been sold online as a research chemical. The toxicity and long-term safety profile of 3-HO-PCE is unknown as it has a very limited history of use, although one study indicates moderate potential toxicity.
In 2005 MeMe Roth began an obesity campaign that led to several appearances in American mainstream media. Programs such as Eat Smart, Move More, Weigh Less, developed in 2007 by writing teams from North Carolina State University and North Carolina Division of Public Health, and now available beyond North Carolina, aim to combat obesity by a combination of healthy eating and increased exercise. In 2008, the state of Pennsylvania enacted a law, the "School Nutrition Policy Initiative," aimed at the elementary level. These "interventions included removing all sodas, sweetened drinks, and unhealthy snack foods from selected schools, 'social marketing' to encourage the consumption of nutritious foods and outreach to parents." The results were a "50 percent drop in incidence of obesity and overweight", as opposed to those individuals who were not part of the study. In the past decade, there have been school-based programs that target the prevention and management of childhood obesity. There is evidence that long term school-based programs have been effective in reducing the prevalence of childhood obesity. For two years, Duke University psychology and global health professor Gary Bennett and eight colleagues followed 365 obese patients who had already developed hypertension. They found that regular medical feedback, self-monitoring, and a set of personalized goals can help obese patients in a primary care setting lose weight and keep it off. Major U.S.
== J == Jacksonian seizure A type of focal seizure that begins in one area of the body (typically a finger or toe) and "marches" to adjacent areas, reflecting orderly spread of abnormal activity in the motor cortex. James–Lange theory A historical theory of emotion proposing that emotions result from physiological responses to stimuli (e.g., "We are afraid because we tremble"). While outdated, it laid groundwork for modern affective neuroscience. Jaw jerk reflex A stretch reflex elicited by tapping the chin, which causes the jaw to jerk upward. Used clinically to assess integrity of the trigeminal nerve and brainstem reflex circuits. Jitter The variability in timing of neural spike trains or signal transmission, especially in motor units or brain-computer interface systems. High jitter can affect signal fidelity. JNK pathway (c-Jun N-terminal kinase pathway) A signaling cascade involved in stress responses, apoptosis, and neurodegeneration. Dysregulation of the JNK pathway is linked to Alzheimer’s disease and neuronal injury. Joubert syndrome A rare genetic disorder characterized by abnormal development of the cerebellar vermis and brainstem, leading to hypotonia, ataxia, abnormal breathing, and developmental delay. Juxtacrine signaling A form of cell-to-cell communication where signaling molecules are transmitted directly through contact, rather than being secreted. Important in neural development and synaptogenesis.
=== Buc–But === Eduard Buchner (1860–1917), German chemist who sounded the death knell of vitalism by discovering cell-free fermentation, 1907 Nobel Prize in Chemistry Stephen L. Buchwald (born 1955), American organic chemist, co-discoverer of palladium-catalyzed C–N bond formation Buchwald–Hartwig amination Mary Van Rensselaer Buell (1893–1969), American chemist who worked on nucleic acids and nucleotides, the relation of hormones to the metabolism of carbohydrates, and other topics in biochemistry Kathryn Bullock (1945–2021), American chemist who co-developed valve-regulated lead-acid batteries Robert Wilhelm Bunsen (1811–1899), German inventor, chemist, discovered the elements caesium and rubidium with Gustav Kirchhoff and invented the Bunsen burner Jeanne Burbank (1915–2002), American chemist who developed lead-acid and silver-zinc batteries for submarines at the United States Naval Research Laboratory Stephanie Burns (born 1955), American organosilicon chemist and past honorary president of Society of Chemical Industry William Merriam Burton (1865–1954), American chemist, developed the first thermal cracking process for crude oil Adolf Butenandt (1903–1995), German biochemist, 1939 Nobel Prize in Chemistry for "work on sex hormones" Alison Butler (PhD 1982), American bioinorganic chemist and metallobiochemist Aleksandr Butlerov (1828–1886), Russian chemist, one of the creators of the theory of chemical structure, who discovered the formose reaction
Sources: en.wikipedia.org
In humans, adipose tissue is located beneath the skin (subcutaneous fat), around internal organs (visceral fat), in bone marrow (yellow bone marrow), intermuscular (muscular system), and in the breast (breast tissue). Adipose tissue is found in specific locations, which are referred to as adipose depots. In addition to adipocytes, which comprise the highest percentage of cells within adipose tissue, other cell types are present, collectively termed stromal vascular fraction (SVF) of cells. SVF includes preadipocytes, fibroblasts, adipose tissue macrophages, and endothelial cells. Adipose tissue contains many small blood vessels. In the integumentary system, which includes the skin, it accumulates in the deepest level, the subcutaneous layer, providing insulation from heat and cold. Around organs, it provides protective padding. However, its main function is to be a reserve of lipids, which can be oxidised to meet the energy needs of the body and to protect it from excess glucose by storing triglycerides produced by the liver from sugars, although some evidence suggests that most lipid synthesis from carbohydrates occurs in the adipose tissue itself. Adipose depots in different parts of the body have different biochemical profiles. Under normal conditions, it provides feedback for hunger and diet to the brain.
== Importance in metabolism == For soil bacteria, creatinase allows for organisms to process the carbon and nitrogen that come from animal wastes, degrading creatine that is made in the kidney, liver, and pancreas and excreted through urine. Animal tissues use creatine to buffer the charging of high-energy carriers during rapid ADP to ATP conversion, which creates 1-methylhydantoin. To avoid build up, animals excrete creatine and creatinine in urine. In humans, creatinase is used in enzymatic measurements of creatinine concentration for the diagnosis of renal and muscle diseases. The enzyme catalyzes the second step of a coupled creatine assay, which is used to monitor the filtration rate of the glomeruli of the kidneys.
Fowler was initially skeptical but was ultimately convinced that Bohr was correct, and by 1915 "spectroscopists had transferred [the Pickering–Fowler series] definitively [from hydrogen] to helium." Bohr's theoretical work on the Pickering series had demonstrated the need for "a re-examination of problems that seemed already to have been solved within classical theories" and provided important confirmation for his atomic theory. In 1938, Russian physicist Pyotr Leonidovich Kapitsa discovered that helium-4 has almost no viscosity at temperatures near absolute zero, a phenomenon now called superfluidity. This phenomenon is related to Bose–Einstein condensation. In 1972, the same phenomenon was observed in helium-3, but at temperatures much closer to absolute zero, by American physicists Douglas D. Osheroff, David M. Lee, and Robert C. Richardson. The phenomenon in helium-3 is thought to be related to pairing of helium-3 fermions to make bosons, in analogy to the Cooper pairs of electrons producing superconductivity. In 1961, Vignos and Fairbank reported the existence of a different phase of solid helium-4, designated the gamma-phase. It exists for a narrow range of pressure between 1.45 K (−271.70 °C; −457.06 °F) and 1.78 K (−271.37 °C; −456.47 °F).
==== Metabolic block ==== Nerve function depends on its blood supply. Arresting or inhibiting the blood supply can deprive nerve tissue of oxygen and other essential nutrients to induce a metabolic block, whereby the nerve is unable to function. This block is purely a physiologic problem such that the structure of the nerve is unchanged. If the metabolic block is short in duration, it is completely reversible with no permanent effects. An example of a metabolic block is when a limb "falls asleep" (temporary numbness, paresthesia, and weakness) due to the position of a limb that restricts blood flow. Complete ischema, such as the application of a tourniquet, is followed by hyperexcitability and then loss of nerve function over 60-90 minutes. The ischema is immediately reversible when the block is released, as long as the duration of ischema is not too long, such as 1-2 hours. The first sign of impairment to intraneural blood flow occurs in the epineural blood vessels at about 20-30mm Hg pressure. At pressures of 60-80mmHg there will be complete ischemia. A metabolic block can also be induced by stretching. In animal studies, venous statis was seen at an 8% stretch and at a 15% stretch the blood supply was completely arrested. It's a frequent occurrence that patients receiving a nerve decompression see an immediate improvement in their symptoms, and this is thought to be the restoration of blood flow after a metabolic block as other forms of functional nerve impairment such as neuropraxia and axonmetesis take longer to recover.
Immediate untreated crush syndrome death is caused by severe head injury, torso injury with damaged abdominal organs, and asphyxia (excessive loss of oxygen). Early untreated crush syndrome death is caused by hyperkalemia and by hypovolemic shock. Late untreated crush syndrome death is caused by renal failure, coagulopathy and hemorrhage, and sepsis. Due to the risk of crush syndrome, current recommendation to nonprofessional first-aiders (in the UK) is to not release those with a crush injury who have been trapped for more than 15 minutes. A torniquet may be used in the event that treatment is not immediately available, as it traps toxins in the ischemic limb, but it is only a method of postponing medical attention. Upon release, isotonic saline is used for fluid resuscitation.
Sources: en.wikipedia.org
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
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.