blood-brain barrier is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-06-18. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Calculated for the free peptide |
| Molecular weight | About 751.9 g/mol | Derived from the sequence |
| Appearance | White to off-white powder | Typical lyophilised form |
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.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Pakistan's untapped coal reserves have been estimated as the fifth largest in the world and equivalent to about 400 billion barrels of oil, exceeding the combined oil reserves of Saudi Arabia and Iran. Daniel Fitzgerald Runde wrote in Forbes in 2016 that Pakistan "could be the 'Saudi Arabia of Coal'." The Reko Diq Mine has one of the world's largest undeveloped copper deposits, with an estimated 15 million tonnes in reserves, and is expected to become the world's fifth largest copper mine upon completion; a feasibility study also estimates that it could produce approximately 17.9 million ounces of gold over its projected 37-year mine life, with total copper and gold reserves valued at over $60 billion at prevailing prices.
Enzymes that use a metal in the active site are called "metallo-carboxypeptidases" (EC number 3.4.17). Other carboxypeptidases that use active site serine residues are called "serine carboxypeptidases" (EC number 3.4.16). Those that use an active site cysteine are called "cysteine carboxypeptidase" (or "thiol carboxypeptidases")(EC number 3.4.18). These names do not refer to the selectivity of the amino acid that is cleaved.
On September 9, 2025, Talarico announced his candidacy for the 2026 U.S. Senate election in Texas. He and U.S. Representative Jasmine Crockett vied for the Democratic nomination. In February 2026, the Houston Chronicle, the Austin American-Statesman, The Dallas Morning News, and the Fort Worth Star-Telegram endorsed Talarico. Later in February, the FCC opened an investigation into Talarico's appearance on The View, citing a potential violation of the equal-time rule. Late-night and talk shows were exempt from the requirement until an FCC rule change in January 2026. On February 16, 2026, Talarico was scheduled to appear on The Late Show with Stephen Colbert. Colbert said CBS canceled the interview because of the Trump administration's "intensifying pressure against broadcast TV networks". He said the network's lawyers had instructed him not to have Talarico on the show or mention the cancellation. Against their advice, he interviewed Talarico and spoke publicly about the cancellation. Colbert accused CBS of censorship and posted the interview to the show's YouTube page instead, where it had gained 7.3 million views by February 18, making it the most viewed interview segment on The Late Show's channel in a year. On March 3, Talarico won the Democratic primary, securing the party's nomination in the November general election. In the general election, he faces Texas Attorney General Ken Paxton, who won the Republican primary runoff on May 26. Former President Barack Obama appeared at an event with Talarico in May 2026.
Sources: en.wikipedia.org
On 25 March 2024 Shehbaz Sharif reconstituted the eight-member Council of Common Interests (CCI) as chairman after a notification was issued. The Prime Minister inducted Khawaja Asif (Defense), Amir Muqam (SAFRON), and Ishaq Dar (Foreign Affairs) into the Council. The composition of the CCI marked the first time a foreign minister had been designated a member, replacing the membership of the finance minister. Abdullah Niazi an editor at Profit claimed that Muhammad Aurangzeb's role in the Cabinet was being undermined by Ishaq Dar, further remarking that the inclusion of Khwaja Asif and Engineer Amir Muqam might indicate Shehbaz Sharif's focus on giving party loyalists greater influence. According to Mushtaq Ghumman, finance ministers were not always included in the CCI however energy and planning ministers were. In the previous Pakistan Democratic Movement (PDM) government under Shehbaz Sharif the finance minister was not included in the CCI. Attaullah Tarar on March 29 would state that “nobody has been replaced or substituted," referencing the constitutional procedure of the CCI. Summaries submitted by different ministries and provincial governments were returned for later resubmission following the re-constitution of the Council. CCI Secretary Omer Rasul stated that the summaries forwarded by ministries, divisions and provincial governments did not conform with the guidelines demarcated in Rules of Procedure of CCI (2010) and were ambiguous whether such cases fell within the purview of the CCI.
Scholars in the history of medicine in China distinguish its doctrines and practice from those of present-day TCM. J. A. Jewell and S. M. Hillier state that the term "Traditional Chinese Medicine" became an established term due to the work of Dr. Kan-Wen Ma, a Western-trained medical doctor who was persecuted during the Cultural Revolution and immigrated to Britain, joining the University of London's Wellcome Institute for the History of Medicine. Ian Johnson says, on the other hand, that the English-language term "traditional Chinese medicine" was coined by "party propagandists" in 1955. Nathan Sivin criticizes attempts to treat medicine and medical practices in traditional China as if they were a single system. Instead, he says, there were 2,000 years of "medical system in turmoil" and speaks of a "myth of an unchanging medical tradition". He urges that "Traditional medicine translated purely into terms of modern medicine becomes partly nonsensical, partly irrelevant, and partly mistaken; that is also true the other way around, a point easily overlooked." TJ Hinrichs observes that people in modern Western societies divide healing practices into biomedicine for the body, psychology for the mind, and religion for the spirit, but these distinctions are inadequate to describe medical concepts among Chinese historically and to a considerable degree today.
=== Neuroprotection === Ciclosporin is in a phase II/III (adaptive) clinical study in Europe to determine its ability to ameliorate neuronal cellular damage and reperfusion injury (phase III) in traumatic brain injury. This multi-center study is being organized by NeuroVive Pharma and the European Brain Injury Consortium using NeuroVive's formulation of ciclosporin called Neurostat (also known by its cardioprotection brand name of Ciclomulsion). This formulation uses a lipid emulsion base instead of cremophor and ethanol. NeuroSTAT was compared to Sandimmune in a phase I study and found to be bioequivalent. In this study, NeuroSTAT did not exhibit the anaphylactic and hypersensitivity reactions found in cremophor- and ethanol-based products. Ciclosporin has been investigated as a possible neuroprotective agent in conditions such as traumatic brain injury, and has been shown in animal experiments to reduce brain damage associated with injury. Ciclosporin blocks the formation of the mitochondrial permeability transition pore, which has been found to cause much of the damage associated with head injury and neurodegenerative diseases. Ciclosporin's neuroprotective properties were first discovered in the early 1990s when two researchers (Eskil Elmér and Hiroyuki Uchino) were conducting experiments in cell transplantation. An unintended finding was that cyclosporin A was strongly neuroprotective when it crossed the blood–brain barrier. This same process of mitochondrial destruction through the opening of the MPT pore is implicated in making traumatic brain injuries much worse.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.
Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.
Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.
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.