Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30536 (PBS)
 9,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Translocator protein (TSPO), formerly known as the peripheral-type benzodiazepine receptor, is an 18 kDa mitochondrial protein primarily involved in steroid biosynthesis in both peripheral and glial cells. It has been extensively reported that TSPO regulates the rate-limiting translocation of cholesterol from the outer to the inner mitochondrial membrane before its transformation by cytochrome P450(scc) into pregnenolone, which is further converted into an array of different steroids. In the brain, neurosteroids such as allopregnanolone and pregnenolone, acting as positive modulators of gamma-aminobutyric type A (GABA(A)) receptors, exert anxiolytic activity. Specific ligands targeting TSPO increase neurosteroid production and for this reason they have been suggested to play an important role in anxiety modulation. Unlike benzodiazepines (Bzs), which represent the most common anti-anxiety drugs administered around the world, selective TSPO ligands have shown anxiolytic effects in animal models without any of the side effects associated with Bzs. Therefore, specific TSPO ligands that are able to promote neurosteroidogenesis may represent the future of therapeutic treatment of anxiety disorders. Furthermore, TSPO expression levels are altered in several different psychiatric disorders in which anxiety is the main symptom. This article reviews the primary and patent literature over the last decade concerning the development of novel TSPO ligands that have resulted effective in various models of anxiety, taking into special consideration their structure-activity relationships.
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PMID:Translocator protein ligands as promising therapeutic tools for anxiety disorders. 1954 67

Long-lasting memories of aversive or stressful events have been associated with the noradrenergic system activation. Alpha-1-adrenergic antagonist prazosin has successfully been used in the last years to treat anxiety disorders related to aversive memories recurrence in humans. Contextual conditioned fear extinction paradigm in rats has been used to better understand the mechanisms involved in the attenuation of defensive behaviour after a traumatic situation. Here we investigated the effects of systemic administration of prazosin in the fear extinction processes. Rats were previously paired in a contextual fear conditioning box (1 footshock, 1 mA, 2s duration), further returning to the same box during three consecutive days receiving an intraperitoneal injection of vehicle or prazosin 30 min before (acquisition of extinction; 0.1 or 0.5mg/kg) or immediately after (consolidation of extinction, 0.5 or 1.5mg/kg) each extinction session (10 min). On the last day, all animals were re-exposed undrugged to the apparatus. Since the medial prefrontal cortex (mPFC) has been described as a key structure in the modulation of conditioned fear extinction, the effects of intra-mPFC microinjection (0.2 microl per side) of vehicle (PBS) or prazosin (0.75 or 2.5 nmol) in the acquisition of fear extinction (10 min before extinction session 1) were further evaluated. Subjects were drug-free re-exposed to the same box in the next day (extinction session 2). The percentage of freezing time was used as the memory retention parameter. The results showed that either systemic or intra-mPFC-alpha-1-adrenergic blockade increased the freezing time in the last extinction sessions, suggesting impairment of the extinction of contextual conditioned fear in rats.
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PMID:Impairment of contextual conditioned fear extinction after microinjection of alpha-1-adrenergic blocker prazosin into the medial prefrontal cortex. 2022 43

Anxiety disorders are frequent and disabling disorders. For short-term treatment, benzodiazepines are useful due to their rapid onset of anxiolytic action. However, these compounds have sedative properties and may induce tolerance, abuse liability and withdrawal symptoms. First-line choices for the long-term treatment are selective serotonin reuptake inhibitors or serotonin-norepinephrine reuptake inhibitors. The major disadvantage of these compounds is their delayed onset of action. It is obvious that there is a need for novel pharmacological approaches that combine a rapid anxiolytic efficacy with the lack of tolerance induction, abuse liability and withdrawal symptoms. A very important target for the development of such compounds is the -amino-butyric-acid (GABA)A receptor. Subtype specific benzodiazepines are being developed, but also phytotherapeutic agents experience a renaissance as GABAA receptor modulators. On the other hand, GABA related compounds, e.g. tiagabine, did not show pronounced anxiolytic efficacy. Neuroactive steroids such as allopregnanolone and tetrahydrodeoxycorticosterone (THDOC) are potent modulators of GABAA receptors. To date synthetic neuroactive steroids could not be established in the treatment of anxiety disorders. Regarding endogenous neurosteroidogenesis, recently the translocator protein (18kDa) (TSPO) has been identified as a potential novel target. TSPO is supposed to play an important role for the synthesis of neuroactive steroids. TSPO ligands may promote the synthesis of neuroactive steroids via induction of cholesterol translocation to the inner mitochondrial membrane. First clinical studies revealed promising results. In this review, we discuss putative compounds affecting the GABAergic system which may provide the basis for fast acting anxiolytics with a favorable side effect profile.
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PMID:Recent developments in potential anxiolytic agents targeting GABAA/BzR complex or the translocator protein (18kDa) (TSPO). 2220 86

Translocator protein 18 kDa (TSPO) in the mitochondrial outer membrane has been implicated in cholesterol transport regulating steroidogenesis. A human single polymorphism associated with anxiety disorders (A147T) and reduced pregnenolone production is adjacent to TSPO's cholesterol binding motif. In a mutant mimicking this polymorphism, we observe a lower level of binding of cholesterol. Further, three residues preceding A147 are more hydrophilic in a bacterial TSPO that has an affinity for cholesterol 1000-fold lower than that of the human form. Converting these residues to the human form in the bacterial homologue strikingly increases the affinity for cholesterol. An important role for this extended motif is further supported by covariance analysis.
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PMID:Identification of a key cholesterol binding enhancement motif in translocator protein 18 kDa. 2563 29

Translocator protein 18 kDa (TSPO) was previously known as the peripheral benzodiazepine receptor (PBR) in eukaryotes, where it is mainly localized to the mitochondrial outer membrane. Considerable evidence indicates that it plays regulatory roles in steroidogenesis and apoptosis and is involved in various human diseases, such as metastatic cancer, Alzheimer's and Parkinson's disease, inflammation, and anxiety disorders. Ligands of TSPO are widely used as diagnostic tools and treatment options, despite there being no clear understanding of the function of TSPO. An ortholog in the photosynthetic bacterium Rhodobacter was independently discovered as the tryptophan-rich sensory protein (TspO) and found to play a role in the response to changes in oxygen and light conditions that regulate photosynthesis and respiration. As part of this highly conserved protein family found in all three kingdoms, the rat TSPO is able to rescue the knockout phenotype in Rhodobacter, indicating functional as well as structural conservation. Recently, a major breakthrough in the field was achieved: the determination of atomic-resolution structures of TSPO from different species by several independent groups. This now allows us to reexamine the function of TSPO with a molecular perspective. In this review, we focus on recently determined structures of TSPO and their implications for potential functions of this ubiquitous multifaceted protein. We suggest that TSPO is an ancient bacterial receptor/stress sensor that has developed additional interactions, partners, and roles in its mitochondrial outer membrane environment in eukaryotes.
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PMID:Translocator Protein 18 kDa (TSPO): An Old Protein with New Functions? 2707 10