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Other names | 3-(2,4-dimethoxy-benzylidene)anabaseine |
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Formula | C19H20N2O2 |
Molar mass | 308.381 g·mol−1 |
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This article needs to be updated.(April 2015) |
GTS-21 (DMXBA or DMBX-anabaseine) is a drug that has been shown to enhance memory and cognitive function. It has been studied for its potential therapeutic uses, particularly in the treatment of neurodegenerative diseases and psychiatric disorders.
It is a derivative of the natural product anabaseine that acts as a partial agonist at neural nicotinic acetylcholine receptors (nAChRs). It binds to both the α4β2 and α7 subtypes, but activates only the α7 to any significant extent. [1] [2] Activation of the α7 nAChR has been shown to have neuroprotective effects and to improve cognitive function, making it an attractive target for drug development.
Both GTS-21 itself and its demethylated active metabolite 4-OH-GTS-21 [3] display nootropic [4] and neuroprotective effects, [5] [6] [7] [8] and GTS-21 is being investigated for the treatment of Alzheimer's disease, [9] [10] nicotine dependence, [11] and, most significantly, for schizophrenia. [12] [13] [14] [15] [16]
Several studies have investigated the effects of GTS-21 in various animal models of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and multiple sclerosis. In these studies, GTS-21 has been shown to have anti-inflammatory and neuroprotective effects, and to improve cognitive function.
A recent study investigated the cholinergic anti-inflammatory pathway (CAP) in rheumatoid arthritis (RA). They used the α7 nicotinic acetylcholine receptor (α7nAChR) agonist GTS-21 to study its role in reducing synovial inflammation in a mice model of collagen-induced arthritis (CIA). GTS-21 lessened inflammation and reduced monocyte infiltration into the synovium. This study highlights a new mechanism by which cholinergic signaling can mitigate synovial inflammation in RA. [17]
Phase one of a clinical trial using DXMBA as a potential treatment for schizophrenia was completed in January of 2005. 12 non-smoking subjects diagnosed with schizophrenia each received 3 daily treatments. The treatments consisted of 150mg of DMXBA, with another dose of 75mg administered 2 hours later, 75mg of DXMBA, with another dose of 37.5mg administered 2 hours later, and a placebo treatment. The order of the doses was randomized over the 3-day course of the treatments. A P50 auditory-evoked test measured a significant effect on sensory gating, and a Repeatable Battery for Assessment of Neuropsychological Status test measured a significant effect on neurocognition. The subjects did not report any symptoms or side effects, however the leukocyte count of one subject decreased from slightly above normal on the placebo, to slightly below normal when administered the higher dose of DXMBA. After receiving no exposure to the drug, the subject's leukocyte count returned to normal 2 days later. [18] This clinical trial untimely was discontinued during phase II. [18] Several other trials focusing on a range of health issues including Alzheimer's, schizophrenia, autism, ADHD, and nicotine use were either discontinued or withdrawn. [19] [20] [21] [22] [23]
Another study of GTS-21 in healthy volunteers found that the drug improved attention and memory performance. [4]
BUN and creatinine levels in the blood are common indicators of kidney function. KIM-1 and NGAL in plasma and kidney tissue are biomarkers of acute/chronic kidney injury. In these experiments, we examine the ability of GTS-21 to attenuate the effects of T2DM on renal function, injury and inflammation. The db/db mice demonstrate a significant increase in plasma BUN (Fig. 1A) and creatinine (Fig. 1B) compared with db/+ mice (P < 0.05 vs. db/+ mice). In contrast, db/db mice treated with GTS-21 demonstrate significant reductions in plasma BUN and creatinine compared with db/db controls (P < 0.05 vs. db/db vehicle). The db/db mice also demonstrate higher levels of plasma and renal injury biomarkers KIM-1 (Fig. 1C,E) and NGAL (Fig. 1D,F) compared to db/ + vehicle controls. GTS-21 significantly attenuated the increase in plasma and renal KIM-1 and NGAL observed in the db/db mice (p < 0.05, vs. db/db vehicle). [24]
IL-6 and HMGB-1 are inflammatory cytokines. Renal and plasma levels of these inflammatory markers were measured to assess the effects of GTS-21 on inflammation in the db/db mice. As shown in Fig. 2, db/db mice demonstrated increased plasma and renal IL-6 and HMGB-1 levels compared with db/+ mice. Treatment with GTS-21 significantly attenuated the elevations in IL-6 and HMGB-1 seen in the db/db mice (P < 0.05, Fig. 2). Collectively, these results provide evidence that α7nAChR activation plays an important role in improving kidney function, modulating renal injury and regulating renal inflammation in db/db mice. [24]
The laboratory name GTS-21 means that it is the 21st chemical compound created by Gainesville (University of Florida in Gainesville) and Tokushima (Taiho Pharmaceutical) Scientists. [25] DMXBA – 3-2,4-dimethoxybenzylidene anabaseine.
Overall, the available evidence suggests that GTS-21 has potential as a therapeutic agent for neurodegenerative diseases and psychiatric disorders. However, more research is needed to fully understand its safety and efficacy, and to determine the optimal dosing and administration regimens.
Cotinine is an alkaloid found in tobacco and is also the predominant metabolite of nicotine, typically used as a biomarker for exposure to tobacco smoke. Cotinine is currently being studied as a treatment for depression, post-traumatic stress disorder (PTSD), schizophrenia, Alzheimer's disease and Parkinson's disease. Cotinine was developed as an antidepressant as a fumaric acid salt, cotinine fumarate, to be sold under the brand name Scotine, but it was never marketed.
Memantine, sold under the brand name Namenda among others, is a medication used to slow the progression of moderate-to-severe Alzheimer's disease. It is taken by mouth.
A muscarinic acetylcholine receptor agonist, also simply known as a muscarinic agonist or as a muscarinic agent, is an agent that activates the activity of the muscarinic acetylcholine receptor. The muscarinic receptor has different subtypes, labelled M1-M5, allowing for further differentiation.
Kynurenic acid is a product of the normal metabolism of amino acid L-tryptophan. It has been shown that kynurenic acid possesses neuroactive activity. It acts as an antiexcitotoxic and anticonvulsant, most likely through acting as an antagonist at excitatory amino acid receptors. Because of this activity, it may influence important neurophysiological and neuropathological processes. As a result, kynurenic acid has been considered for use in therapy in certain neurobiological disorders. Conversely, increased levels of kynurenic acid have also been linked to certain pathological conditions.
Tropisetron is a serotonin 5-HT3 receptor antagonist used mainly as an antiemetic to treat nausea and vomiting following chemotherapy, although it has been used experimentally as an analgesic in cases of fibromyalgia.
A nicotinic agonist is a drug that mimics the action of acetylcholine (ACh) at nicotinic acetylcholine receptors (nAChRs). The nAChR is named for its affinity for nicotine.
The alpha-7 nicotinic receptor, also known as the α7 receptor, is a type of nicotinic acetylcholine receptor implicated in long-term memory, consisting entirely of α7 subunits. As with other nicotinic acetylcholine receptors, functional α7 receptors are pentameric [i.e., (α7)5 stoichiometry].
Ispronicline is an experimental drug which acts as a partial agonist at neural nicotinic acetylcholine receptors. It progressed to phase II clinical trials for the treatment of dementia and Alzheimer's disease, but is no longer under development.
ABT-418 is a drug developed by Abbott, that has nootropic, neuroprotective and anxiolytic effects, and has been researched for treatment of both Alzheimer's disease and ADHD. It acts as an agonist at neural nicotinic acetylcholine receptors, subtype-selective binding with high affinity to the α4β2, α7/5-HT3, and α2β2 nicotinic acetylcholine receptors but not α3β4 receptors ABT-418 was reasonably effective for both applications and fairly well tolerated, but produced some side effects, principally nausea, and it is unclear whether ABT-418 itself will proceed to clinical development or if another similar drug will be used instead.
Xanomeline is a small molecule muscarinic acetylcholine receptor agonist that was first synthesized in a collaboration between Eli Lilly and Novo Nordisk as an investigational therapeutic being studied for the treatment of central nervous system (CNS) disorders.
Bradanicline is a drug which was being developed by Targacept that acts as a partial agonist at the α7 subtype of the neural nicotinic acetylcholine receptors. It showed cognitive enhancing effects in animal studies, and was being developed through a collaboration between Targacept and AstraZeneca as a potential treatment for schizophrenia and attention deficit disorder. Phase I clinical trials were completed successfully, and it was in phase II trials.
PNU-282,987 is a drug that acts as a potent and selective agonist for the α7 subtype of neural nicotinic acetylcholine receptors. In animal studies, it shows nootropic effects, and derivatives may be useful in the treatment of schizophrenia, although PNU-282,987 is not suitable for use in humans because of excessive inhibition of the hERG antitarget. PNU-282987 has been shown to initiate signaling that leads to adult neurogeneis in mammals.
PHA-543,613 is a drug that acts as a potent and selective agonist for the α7 subtype of neural nicotinic acetylcholine receptors, with a high level of brain penetration and good oral bioavailability. It is under development as a possible treatment for cognitive deficits in schizophrenia. It reduces excitotoxicity and protects striatal dopaminergic neurons in rat models. It also potentiates cognitive enhancement from memantine, decreases dynorphin release and inhibits GSK-B3.
SSR180711 is a drug that acts as a potent and selective partial agonist for the α7 subtype of neural nicotinic acetylcholine receptors. In animal studies, it shows nootropic effects and may be useful in the treatment of schizophrenia.
TC-1698 is a drug developed by Targacept which acts as a partial agonist for the α7 subtype of neural nicotinic acetylcholine receptors. It has neuroprotective effects in animal studies, and has been used as a lead compound to find further potent derivatives.
WAY-317538 (SEN-12333) is a drug that acts as a potent and selective full agonist for the α7 subtype of neural nicotinic acetylcholine receptors. It was not the most potent compound in the series, but was selected for further development on the basis of its high selectivity over related receptors, ease of synthesis, and good in vivo properties including high oral bioavailability and good brain penetration. It has nootropic and neuroprotective effects in animal studies, and is being investigated as a potential treatment for neurodegenerative and neurocognitive conditions including Alzheimer's disease and schizophrenia.
Encenicline is a selective partial agonist of the α7 nicotinic receptor. It was in phase III clinical trials for the treatment of cognitive impairment in schizophrenia, but failed to meet the study endpoints in 2016.
Anabaseine (3,4,5,6-tetrahydro-2,3′-bipyridine) is an alkaloid toxin produced by Nemertines worms and Aphaenogaster ants. It is structurally similar to nicotine and anabasine. Similarly, it has been shown to act as an agonist on most nicotinic acetylcholine receptors in the central nervous system and peripheral nervous system.
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