epithalamin raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-05-11. Anything still debated is marked as such rather than presented as settled.
Identity is normally established by reversed-phase high-performance liquid chromatography combined with mass spectrometry, a pairing that separates components and confirms molecular mass at once. Purity is quoted as a percentage from the chromatogram, and figures above ninety-five percent are a frequent commercial specification. Amino acid analysis or sequencing supplies further confirmation when required. Because many short peptides behave similarly under chromatography, retention time alone does not establish sequence; the mass measurement is what separates one tetrapeptide from another, and certificates should report both.
Short peptides such as AEDG are normally supplied as a freeze-dried solid and are kept dry, cold, and shielded from light. Holding at minus twenty degrees Celsius is common for the long term, while a refrigerator suffices for brief periods before use. The material takes up moisture to some degree, so containers should stay sealed and be allowed to reach room temperature before opening, which limits condensation on the contents. Repeated warming and cooling of a single container is discouraged because it admits water and can lower the amount of intact peptide.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
| Property | Value | Notes |
|---|---|---|
| Sequence | Ala-Glu-Asp-Gly | Written in three-letter amino acid code |
| Single-letter code | AEDG | Form used in most catalogue entries |
| Typical purity specification | 95 percent or higher | Value read from the HPLC chromatogram |
| Storage, dry solid | Minus 20 degrees Celsius, desiccated | Sealed container, protected from light |
| Handling, solution | Divide into single-use portions | Limits losses from freeze-thaw cycling |
Because epitalon has no pharmacopoeial monograph, quality assessment depends on supplier documentation and independent testing. Certificates of analysis typically report a purity figure from a single chromatographic run, a measured mass and sometimes an appearance description, but methods and acceptance criteria are not harmonised across vendors. Third-party laboratories can repeat identity and purity measurements, and mismatches between labelled and measured peptide content have been described for research peptides generally. What constitutes adequate identity confirmation for a molecule of this size stays an open question, since mass agreement alone does not separate closely related sequences.
Identity testing for epitalon relies on reversed-phase high-performance liquid chromatography for purity and mass spectrometry for mass confirmation. Because the sequence contains no tryptophan or tyrosine, ultraviolet detection at 280 nanometres is insensitive, so chromatographic methods usually monitor absorbance near 214 nanometres, where the peptide backbone absorbs. Electrospray ionisation or matrix-assisted laser desorption/ionisation then checks the intact mass against the expected value near 390 daltons. Peptide mapping or amino acid analysis after acid hydrolysis can supplement these measurements, although such confirmatory work is seldom reported on commercial certificates of analysis.
Stability of the tetrapeptide follows ordinary peptide chemistry rather than any unusual structural feature. The aspartate-glycine pair is prone to aspartimide formation under mildly basic or neutral conditions, and deamidation can follow, altering both mass and chromatographic retention. Dry lyophilised powder kept at or below minus twenty degrees Celsius is the usual handling recommendation, with repeated freeze-thaw cycles avoided. Once dissolved in neutral aqueous buffer, degradation proceeds over days to weeks depending on pH and temperature, while acidic conditions generally slow the aspartimide route. A formal stability-indicating study has not been published in the indexed literature.
Several names circulate for the same molecule, including epitalon, epithalone, epithalamin tetrapeptide, and the sequence code AEDG. A CAS registry number, 307297-39-8, is commonly cited for it, though catalogue entries should be checked against supplier documentation because mislabelled records occur. In its usual form the peptide carries free amino and carboxyl termini and is neither glycosylated nor lipidated. Researchers distinguish the defined tetrapeptide from epithalamin itself, a crude pineal preparation containing many peptides that is not chemically characterised.
Material supplied for laboratory use is normally a lyophilised white to off-white powder that dissolves readily in water and in isotonic saline. Lyophilised cakes are hygroscopic and should be equilibrated to room temperature before opening to limit condensation on the solid. Solutions are typically prepared at milligram-per-millilitre concentrations and divided into single-use aliquots, because repeated freeze–thaw cycles degrade short peptides. Aqueous solutions are far less stable than the dry powder, and identity is usually verified by mass spectrometry alongside purity estimation from reversed-phase high-performance liquid chromatography.
Epitalon is a synthetic linear tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and the calculated mass is approximately 390.35 g/mol. The compound is made by solid-phase peptide synthesis rather than extracted from tissue, although early work described it as a short fragment of a peptide fraction obtained from bovine pineal extract. In the research literature the spelling epitalon and the variant epithalone both appear, while AEDG is the standard code used in peptide nomenclature.
Freeze-dried epitalon is normally kept at minus twenty degrees Celsius in a sealed, desiccated container, protected from light. Short excursions at ambient temperature during shipping are generally tolerated, but repeated warming and cooling cycles encourage moisture uptake, which shortens shelf life. Once dissolved, the peptide is far less stable than the solid: aqueous solutions are subject to hydrolysis and to deamidation at the aspartate and glutamate residues. Working solutions are therefore held refrigerated and used within days, and repeated freezing and thawing of the same vial is best avoided.
Identity and purity are checked by reversed-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, where the peptide bond absorbs. Mass spectrometry confirms the expected mass and reveals whether truncation products or adducts are present. Acid hydrolysis followed by amino acid analysis gives the residue ratio, which should approximate one alanine, one glutamate, one aspartate and one glycine. Counter-ions such as acetate or trifluoroacetate remain in the dried product and lower net peptide content, so a stated purity figure on a label does not by itself describe how much peptide a vial holds.
NETA is used as a hormonal contraceptive in combination with estrogen, in the treatment of gynecological disorders such as abnormal uterine bleeding, and as a component of menopausal hormone therapy for the treatment of menopausal symptoms. NETA is available in the form of tablets for use by mouth both alone and in combination with estrogens including estradiol, estradiol valerate, and ethinylestradiol. Transdermal patches providing a combination of 50 μg/day estradiol and 0.14 or 0.25 mg/day NETA are available under the brand names CombiPatch and Estalis. NETA was previously available for use by intramuscular injection in the form of ampoules containing 20 mg NETA, 5 mg estradiol benzoate, 8 mg estradiol valerate, and 180 mg testosterone enanthate in oil solution under the brand name Ablacton to suppress lactation in postpartum women. Side effects of NETA include menstrual irregularities, headaches, nausea, breast tenderness, mood changes, acne, increased hair growth, and others.
Hippocrates in his writings discussed the use of silver in wound care. At the beginning of the twentieth century surgeons routinely used silver sutures to reduce the risk of infection. In the early 20th century, physicians used silver-containing eyedrops to treat ophthalmic problems, for various infections, and sometimes internally for diseases such as tropical sprue, epilepsy, gonorrhea, and the common cold. During World War I, soldiers used silver leaf to treat infected wounds. In the 1840s, founder of gynecology J. Marion Sims employed silver wire, which he had a jeweler fashion, as a suture in gynecological surgery. This produced very favorable results when compared with its predecessors, silk and catgut. Prior to the introduction of modern antibiotics, colloidal silver was used as a germicide and disinfectant. With the development of modern antibiotics in the 1940s, the use of silver as an antimicrobial agent diminished, although it retains some use in medicinal compounds today. Silver sulfadiazine (SSD) is a compound containing silver and the antibiotic sodium sulfadiazine, which was developed in 1968.
The US Food and Drug Administration (FDA) requires all antidepressants, including venlafaxine, to carry a black box warning with a generic warning about a possible suicide risk. A 2014 meta-analysis of 21 clinical trials of venlafaxine for the treatment of depression in adults found that compared to placebo, venlafaxine reduced the risk of suicidal thoughts and behavior. A study conducted in Finland followed more than 15,000 patients for 3.4 years. Venlafaxine increased suicide risk by 60% (statistically significant), as compared to no treatment. At the same time, fluoxetine (Prozac) halved the suicide risk. In a study sponsored by Wyeth, which produces and markets venlafaxine, the data on more than 200,000 cases were obtained from the UK general practice research database. At baseline, patients prescribed venlafaxine had a greater number of risk factors for suicide (such as prior suicide attempts) than patients treated with other anti-depressants. The patients taking venlafaxine had a significantly higher risk of suicide than the ones on fluoxetine or citalopram (Celexa). After adjusting for known risk factors, venlafaxine was associated with an increased risk of suicide relative to fluoxetine and dothiepin which was not statistically significant. A statistically significant greater risk for attempted suicide remained after adjustment, but the authors concluded that it could be due to residual confounding.
Pizotifen is a serotonin antagonist acting mainly at the 5-HT2A, 5-HT2B, and 5-HT2C receptors. It also has some activity as an antihistamine as well as some anticholinergic activity. The drug binds non-selectively to many targets, including serotonin, dopamine, adrenergic, histamine, and muscarinic acetylcholine receptors. Besides its serotonin 5-HT2 receptor antagonism, pizotifen is a low-potency moderate-efficacy partial agonist of the serotonin 5-HT1A receptor. Pizotifen is able to dose-dependently and fully antagonize the discriminative stimulus effects of the serotonin–norepinephrine–dopamine releasing agent and serotonin 5-HT2 receptor agonist MDMA in rodent drug discrimination tests. Conversely, the related drug cyproheptadine was only partially effective and clozapine was ineffective. All three of these agents, pizotifen, cyproheptadine, and clozapine act as non-selective monoamine receptor antagonists. Pizotifen also fully blocks the effects of serotonergic psychedelics, including LSD, mescaline, 5-MeO-DMT, and DOM, in drug discrimination tests. The antimigraine activity of pizotifen might be specifically due to serotonin 5-HT2B receptor blockade.
Histone-arginine N-methyltransferase (EC 2.1.1.125, histone protein methylase I, nuclear protein (histone) N-methyltransferase, protein methylase I, S-adenosyl-L-methionine:histone-arginine omega-N-methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:histone-arginine Nomega-methyltransferase. This enzyme catalyses the following chemical reaction
Sources: en.wikipedia.org
== Supplement use and research == Grape seed extract is sold as a dietary supplement. Oral administration of grape seed extract (dose and frequency unreported) was well tolerated in people over 14 weeks. Side effects may include itchy scalp, dizziness, headache, and nausea. A 2019 meta-analysis suggested that grape seed extract might help to lower concentrations of LDL cholesterol, total cholesterol, triglycerides, and the inflammatory marker, C-reactive protein. However, each of the studies was small in size, possibly affecting interpretation of the analysis. A 2016 meta-analysis concluded that grape seed extract, in a dose of under 800 milligrams per day over at least 8 weeks, might help to reduce systolic and diastolic blood pressure. People with metabolic syndrome had a more significant outcome (average of a 8½ mmHg decrease in systolic blood pressure) than in healthy subjects. The authors concluded that heterogeneity in the study designs and small sample sizes involved in the meta-analysis introduced uncertainty in the results, and that larger-scale, long-term, multiple-dose studies in people with high blood pressure were warranted.
=== Dendritic secretion === Supraoptic neurons have typically 1-3 large dendrites, most of which projecting ventrally to form a mat of process at the base of the nucleus, called the ventral glial lamina. The dendrites receive most of the synaptic terminals from afferent neurons that regulate the supraoptic neurons, but neuronal dendrites are often actively involved in information processing, rather than being simply passive receivers of information. The dendrites of supraoptic neurons contain large numbers of neurosecretory vesicles that contain oxytocin and vasopressin, and they can be released from the dendrites by exocytosis. The oxytocin and vasopressin that is released at the posterior pituitary gland enters the blood, and cannot re-enter the brain because the blood–brain barrier does not allow oxytocin and vasopressin through, but the oxytocin and vasopressin that is released from dendrites acts within the brain. Oxytocin neurons themselves express oxytocin receptors, and vasopressin neurons express vasopressin receptors, so dendritically released peptides "autoregulate" the supraoptic neurons. Francoise Moos and Phillipe Richard first showed that the autoregulatory action of oxytocin is important for the milk-ejection reflex. These peptides have relatively long half-lives in the brain (about 20 minutes in the CSF), and they are released in large amounts in the supraoptic nucleus, and so they are available to diffuse through the extracellular spaces of the brain to act at distant targets.
== Etymology == A loanword from Japanese, umami can be translated as "pleasant savory taste". The original word has various orthographies: うまみ, うま味, 旨味, meaning "deliciousness". However, in its original sense, it is normally used in its adjectival form umai (うまい, 旨い). The arrangement of glyphs うま味 for umami was proposed in 1908 by Kikunae Ikeda to refer to the particular savory component he was researching. While the written forms are often used interchangeably, in the 1980s Japanese researchers suggested that うま味 should be used for the flavor while 旨味 is the more general sense of tasty.
== Prognosis == The use of DMARDs in the management of JIA have made disease-free remission achievable for the majority of children with JIA. Clinical remission can be defined as the absence of signs and symptoms of inflammatory disease activity, including extra-articular manifestations of the disease. Differentiating subtypes of JIA helps to target treatment and leads to more positive outcomes, however subtype is not the only predictor of JIA outcome. Poor prognostic factors include arthritis of the hip, cervical spine, ankles or wrists; prolonged elevation of inflammatory markers; and radiographic evidence of joint damage including erosions or joint space narrowing. Patients with RF-positive polyarthritis often have worse outcomes associated with more aggressive disease. Despite this, the probability of this subgroup achieving inactive disease at least once within five years was shown to be 90% in a large Canadian study. Research is currently being undertaken into clinical prediction models to allow earlier identification of children who are likely to have a worse prognosis. Compliance with therapy, especially medications, has a positive correlation with disease outcome. Disease recurrence after medical therapy discontinuation is high, with 30-100% of children having clinical relapse of disease after treatment discontinuation. It has been previously suggested that children with JIA are at an increased risk of malignancies when being treated with anti-TNF therapy.
Nitrogen forms nine molecular oxides, some of which were the first gases to be identified: N2O (nitrous oxide), NO (nitric oxide), N2O3 (dinitrogen trioxide), NO2 (nitrogen dioxide), N2O4 (dinitrogen tetroxide), N2O5 (dinitrogen pentoxide), N4O (nitrosylazide), and N(NO2)3 (trinitramide). All are thermally unstable towards decomposition to their elements. One other possible oxide that has not yet been synthesised is oxatetrazole (N4O), an aromatic ring. Nitrous oxide (N2O), better known as laughing gas, is made by thermal decomposition of molten ammonium nitrate at 250 °C. This is a redox reaction and thus nitric oxide and nitrogen are also produced as byproducts. It is mostly used as a propellant and aerating agent for sprayed canned whipped cream, and was formerly commonly used as an anaesthetic. Despite appearances, it cannot be considered to be the anhydride of hyponitrous acid (H2N2O2) because that acid is not produced by the dissolution of nitrous oxide in water. It is rather unreactive (not reacting with the halogens, the alkali metals, or ozone at room temperature, although reactivity increases upon heating) and has the unsymmetrical structure N–N–O (N≡N+O−↔−N=N+=O): above 600 °C it dissociates by breaking the weaker N–O bond. Nitric oxide (NO) is the simplest stable molecule with an odd number of electrons. In mammals, including humans, it is an important cellular signalling molecule involved in many physiological and pathological processes. It is formed by catalytic oxidation of ammonia.
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography is run alongside mass spectrometry. The chromatogram separates components and gives a purity figure, while the mass spectrum confirms that the measured molecular mass matches the expected sequence. Neither measurement on its own is treated as sufficient.
Long-term holding is usually at minus twenty degrees Celsius in a sealed, desiccated container. A refrigerator is adequate for short intervals before use. Light exposure is normally avoided as well. Allowing a cold container to warm before opening reduces moisture condensation on the contents.
Repeated cycles are generally avoided. Each freeze and thaw can promote aggregation or loss of peptide to container surfaces, which reduces the amount available for later work. Dividing a solution into single-use portions at the outset is the usual way to limit this problem.
The peptide contains four residues in the order alanine, glutamate, aspartate and glycine, abbreviated AEDG. The chain is linear and held together by three peptide bonds. Its calculated mass for the uncharged free form is about 390.3 daltons.