Alpidem, sold under the brand name Ananxyl, is a nonbenzodiazepine anxiolytic 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.
Bretazenil (Ro16-6028) is an imidazopyrrolobenzodiazepine anxiolytic drug which is derived from the benzodiazepine family, and was invented in 1988. It is most closely related in structure to the GABA antagonist flumazenil, although its effects are somewhat different. It is classified as a high-potency benzodiazepine due to its high affinity binding to benzodiazepine binding sites where it acts as a partial agonist. Its profile as a partial agonist and preclinical trial data suggests that it may have a reduced adverse effect profile. In particular bretazenil has been proposed to cause a less strong development of tolerance and withdrawal syndrome. Bretazenil differs from traditional 1,4-benzodiazepines by being a partial agonist and because it binds to α1, α2, α3, α4, α5 and α6 subunit containing GABAA receptor benzodiazepine receptor complexes. 1,4-benzodiazepines bind only to α1, α2, α3 and α5GABAA benzodiazepine receptor complexes.
(+)-CPCA is a stimulant drug similar in structure to pethidine and to RTI-31, but nocaine is lacking the two-carbon bridge of RTI-31's tropane skeleton. This compound was first developed as a substitute agent for cocaine.
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.
Panadiplon (U-78875) is an anxiolytic drug with a novel chemical structure that is not closely related to other drugs of this type. It has a similar pharmacological profile to the benzodiazepine family of drugs, but with mainly anxiolytic properties and relatively little sedative or amnestic effect, and so is classified as a nonbenzodiazepine anxiolytic.
Imidazenil is an experimental anxiolytic drug which is derived from the benzodiazepine family, and is most closely related to other imidazobenzodiazepines such as midazolam, flumazenil, and bretazenil.
L-838,417 is an anxiolytic drug used in scientific research. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic. The compound was developed by Merck, Sharp and Dohme.
SL651498 is an anxiolytic and anticonvulsant drug used in scientific research, with a chemical structure most closely related to β-carboline derivatives such as abecarnil and gedocarnil. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic.
Y-23684 is an anxiolytic drug with a novel chemical structure, which is used in scientific research. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic.
ELB-139 (LS-191,811) is an anxiolytic drug with a novel chemical structure, which is used in scientific research. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic.
1-Amino-5-phosphonoindan-1-carboxylic acid (APICA) is a drug that is used in neuroscience research. It is a selective antagonist for the group II metabotropic glutamate receptors (mGluR2/3), and has been useful in the study of this receptor subfamily.
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-1-43 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.
Adatanserin is a mixed 5-HT1A receptor partial agonist and 5-HT2A and 5-HT2C receptor antagonist. It was under development by Wyeth as an antidepressant but was ultimately not pursued.
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.
Vassilios Papadopoulos, DPharm, PhD, DSc (hon), born February 18, 1961, in Athens, Greece, is a scholar, researcher, inventor, professor, and university administrator who has served as dean of the USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences at the University of Southern California in Los Angeles, California since 2016. Previously, he was the associate vice president and director of the Biomedical Graduate Research Organization at Georgetown University from 2005 to 2007, and the executive director and chief scientific officer of the Research Institute of the McGill University Health Center from 2007 to 2015.
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