Alpidem, sold under the brand name Ananxyl, is a nonbenzodiazepine medication which was briefly used to treat anxiety disorders but is no longer marketed. It was previously marketed in France, but was discontinued due to liver toxicity. Alpidem is taken by mouth.
PK-11195 is an isoquinoline carboxamide which binds selectively to the peripheral benzodiazepine receptor (PBR). It is one of the most commonly used PBR ligands due to its high affinity for the PBR in all species, although it is starting to be replaced by newer and more selective ligands.
Translocator protein (TSPO) is an 18 kDa protein mainly found on the outer mitochondrial membrane. It was first described as peripheral benzodiazepine receptor (PBR), a secondary binding site for diazepam, but subsequent research has found the receptor to be expressed throughout the body and brain. In humans, the translocator protein is encoded by the TSPO gene. It belongs to a family of tryptophan-rich sensory proteins. Regarding intramitochondrial cholesterol transport, TSPO has been proposed to interact with StAR to transport cholesterol into mitochondria, though evidence is mixed.
Etifoxine is an anxiolytic and anticonvulsant drug developed by Hoechst in the 1960s. It is sold in approximately 40 countries for anxiety disorders, without the sedation and ataxia associated with benzodiazepine drugs. It has similar anxiolytic effects to benzodiazepine drugs, but is structurally distinct, although it has structural elements in common with them. Studies suggest is as effective as lorazepam as an anxiolytic, but has fewer side effects. Etifoxine is not approved by the U.S. Food and Drug Administration. The European Medicines Agency (EMA) started a review procedure regarding the effectiveness and safety of etifoxine following a French study that compares etifoxine's effectiveness to placebo and lorazepam. In January 2022, the EMA "finalized its review of Stresam and concluded that the medicine can continue to be used for the treatment of anxiety disorders, but it must not be used in patients who previously had severe skin reactions or severe liver problems after taking etifoxine."
The free fraction is a parameter in pharmacokinetics and receptor-ligand kinetics. One speaks of two different free fractions:
Affibody molecules are small, robust proteins engineered to bind to a large number of target proteins or peptides with high affinity, imitating monoclonal antibodies, and are therefore a member of the family of antibody mimetics. Affibody molecules are used in biochemical research and are being developed as potential new biopharmaceutical drugs. These molecules can be used for molecular recognition in diagnostic and therapeutic applications.
Emapunil is an anxiolytic drug which acts as a selective agonist at the peripheral benzodiazepine receptor, also known as the mitochondrial 18 kDa translocator protein or TSPO. This protein has multiple functions, among which is regulation of steroidogenesis, particularly the production of neuroactive steroids such as allopregnanolone in the brain. In both animal and human trials, emapunil produced fast acting anxiolytic and anti-panic effects, without producing sedation or withdrawal symptoms following cessation of use. Emapunil is also used in its 11C radiolabelled form to map the distribution of TSPO receptors in the brain.
FGIN-1-27 is an anxiolytic drug which acts as a selective agonist at the peripheral benzodiazepine receptor, also known as the mitochondrial 18 kDa translocator protein or TSPO. It is thought to produce anxiolytic effects by stimulating steroidogenesis of neuroactive steroids such as allopregnanolone.
FGIN-1-43 is an anxiolytic drug which acts as a selective agonist at the peripheral benzodiazepine receptor, also known as the mitochondrial 18 kDa translocator protein or TSPO. It is thought to produce anxiolytic effects by stimulating steroidogenesis of neuroactive steroids such as allopregnanolone, and is several times more potent than the related drug FGIN-127.
SSR-180,575 is a drug which acts as a selective agonist at the peripheral benzodiazepine receptor, also known as the mitochondrial 18 kDa translocator protein or TSPO. It has been shown to have neuroprotective and cardioprotective effects and to stimulate steroidogenesis of pregnenolone in the brain, which may be linked to its neuroprotective action.
DAA-1097 is a drug which acts as a potent and selective agonist at the peripheral benzodiazepine receptor, also known as the mitochondrial 18 kDa translocator protein or TSPO, but with no affinity at central benzodiazepine receptors. It has anxiolytic effects in animal studies.
DAA-1106 is a drug which acts as a potent and selective agonist at the peripheral benzodiazepine receptor, also known as the mitochondrial 18 kDa translocator protein or TSPO, but with no affinity at the GABAA receptor. It has anxiolytic effects in animal studies. DAA-1106 has a sub-nanomolar binding affinity (Ki) of 0.28nM, and has been used extensively in its 3H or 11C radiolabelled form to map TSPO in the body and brain, which has proved especially helpful in monitoring the progress of neurodegenerative diseases such as Alzheimer's disease.
Ro5-4864 (4'-chlorodiazepam) is a drug which is a benzodiazepine derivative of diazepam. However unlike most benzodiazepine derivatives, Ro5-4864 lacks affinity for GABAA receptors and lacks typical benzodiazepine effects, instead being sedative yet also convulsant and anxiogenic in effects. Ro5-4864 was found to be a potent ligand for the "peripheral benzodiazepine receptor", later renamed to mitochondrial translocator protein 18kDa (TSPO). Despite its convulsant effects, at lower doses Ro5-4864 has proved to be neuroprotective and has become widely used for research into the role of the TSPO protein in neurotoxicity. In vitro studies and rodent models also suggest the possibility of analgesic, antidepressant, cardioprotective, and anti-cancer effects.
Brain positron emission tomography is a form of positron emission tomography (PET) that is used to measure brain metabolism and the distribution of exogenous radiolabeled chemical agents throughout the brain. PET measures emissions from radioactively labeled metabolically active chemicals that have been injected into the bloodstream. The emission data from brain PET are computer-processed to produce multi-dimensional images of the distribution of the chemicals throughout the brain.
Mefway is a serotonin 5-HT1A receptor antagonist used in medical research, usually in the form of mefway (18F) as a positron emission tomography (PET) radiotracer.
DPA-714 or N,N-diethyl-2-[4-(2-fluoroethoxy)phenyl]-5,7-dimethylpyrazolo[1,5-a]pyrimidine-3-acetamide is a selective ligand for the translocator protein (TSPO) currently under evaluation for several clinical applications. For this reason, a practical, multigram synthetic route for its preparation has been described.
Nifene is a high affinity, selective nicotinic α4β2* receptor partial agonist used in medical research for nicotinic acetylcholine receptors, usually in the form of nifene (18F) as a positron emission tomography (PET) radiotracer.
LY-2459989 is a silent antagonist of the κ-opioid receptor (KOR) that has been developed by Eli Lilly as a radiotracer of the aforementioned receptor, labeled either with carbon-11 or fluorine-18. It possesses high affinity for the KOR and is highly selective for it over the μ-opioid receptor and the δ-opioid receptor. LY-2459989 is a fluorine-containing analogue and follow-up compound of LY-2795050, the first KOR-selective antagonist radiotracer. Relative to LY-2795050, LY-2459989 displays 4-fold higher affinity for the KOR and similar selectivity and also possesses greatly improved central nervous system permeation. The drug appears to possess a short duration of action, with only 25% remaining in serum at 30 minutes post-injection in rhesus monkeys, making it an ideal agent for application in biomedical imaging, for instance in positron emission tomography (PET).
Andreas Kjær is a Danish physician-scientist and European Research Council (ERC) advanced grantee. He is professor at the University of Copenhagen and chief physician at Rigshospitalet, the National University Hospital of Denmark. He is board certified in Nuclear Medicine and his research is focused on molecular imaging with PET and PET/MRI and targeted radionuclide therapies (theranostics) in cancer. His achievements include development of several new PET tracers that have reached first-in-human clinical use. He has published more than 400 peer-review articles, filed 10 patents, supervised more than 40 PhD students and received numerous prestigious scientific awards over the years. He is a member of the Danish Academy of Technical Sciences
Crystal C. Watkins Johansson is an American neuroscientist and psychiatrist and associate professor of neuroscience at Johns Hopkins University School of Medicine as well as the director of the Sheppard Pratt Memory Clinic in Neuropsychiatry in Baltimore, Maryland. Johansson was the first Black female Meyerhoff Scholar to obtain an MD/PhD from the University of Maryland, Baltimore County. During her MD/PhD she developed a novel treatment for gastrointestinal in patients with diabetes that led to a patent for a pharmacological compound in 2000. Johansson is a practicing neuropsychiatrist with a focus on geriatric psychiatry and she conducts brain imaging research as well as research on cancer in African American women.
