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Kumrungsee T. Is hepatic GABA transaminase a promising target for obesity and epilepsy treatments? Biosci Biotechnol Biochem 2024; 88:839-849. [PMID: 38749549 DOI: 10.1093/bbb/zbae066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 05/05/2024] [Indexed: 07/23/2024]
Abstract
γ-Aminobutyric acid (GABA) transaminase (GABA-T) is a GABA-degrading enzyme that plays an essential role in regulating GABA levels and maintaining supplies of GABA. Although GABA in the mammalian brain was discovered 70 years ago, research on GABA and GABA-T has predominantly focused on the brain. Notwithstanding the high activity and expression of GABA-T in the liver, the exact functions of GABA-T in the liver remain unknown. This article reviews the up-to-date information on GABA-T in the liver. It presents recent findings on the role of liver GABA-T in food intake suppression and appetite regulation. Finally, the potential functions of liver GABA-T in other neurological diseases, natural GABA-T inhibitors, and future perspectives in this research area are discussed.
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Affiliation(s)
- Thanutchaporn Kumrungsee
- Program of Food and AgriLife Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
- Smart Agriculture, Graduate School of Innovation and Practice for Smart Society, Hiroshima University, Hiroshima, Japan
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Nabbout R, Kuchenbuch M, Chiron C, Curatolo P. Pharmacotherapy for Seizures in Tuberous Sclerosis Complex. CNS Drugs 2021; 35:965-983. [PMID: 34417984 DOI: 10.1007/s40263-021-00835-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/05/2021] [Indexed: 01/18/2023]
Abstract
Epilepsy is one of the main symptoms affecting the lives of individuals with tuberous sclerosis complex (TSC), causing a high rate of morbidity. Individuals with TSC can present with various types of seizures, epilepsies, and epilepsy syndromes that can coexist or appear in relation to age. Focal epilepsy is the most frequent epilepsy type with two developmental and epileptic encephalopathies: infantile spasms syndrome and Lennox-Gastaut syndrome. Active screening and early management of epilepsy is recommended in individuals with TSC to limit its consequences and its impact on quality of life, cognitive outcome and the economic burden of the disease. The progress in the knowledge of the mechanisms underlying epilepsy in TSC has paved the way for new concepts in the management of epilepsy related to TSC. In addition, we are moving from traditional "reactive" and therapeutic choices with current antiseizure medications used after the onset of seizures, to a proactive approach, aimed at predicting and preventing epileptogenesis and the onset of epilepsy with vigabatrin, and to personalized treatments with mechanistic therapies, namely mechanistic/mammalian target of rapamycin inhibitors. Indeed, epilepsy linked to TSC is one of the only epilepsies for which a predictive and preventive approach can delay seizure onset and improve seizure response. However, the efficacy of such interventions on long-term cognitive and psychiatric outcomes is still under investigation.
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Affiliation(s)
- Rima Nabbout
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker Enfants Malades University Hospital, APHP, Université de Paris, 149 rue de Sèvres, 75015, Paris, France.
- UMR 1163, Institut National de la Santé et de la Recherche Médicale (INSERM), Imagine Institute, Université de Paris, Paris, France.
| | - Mathieu Kuchenbuch
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker Enfants Malades University Hospital, APHP, Université de Paris, 149 rue de Sèvres, 75015, Paris, France
- UMR 1163, Institut National de la Santé et de la Recherche Médicale (INSERM), Imagine Institute, Université de Paris, Paris, France
| | - Catherine Chiron
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker Enfants Malades University Hospital, APHP, Université de Paris, 149 rue de Sèvres, 75015, Paris, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), UMR 1141, Neurospin, Gif sur Yvette, France
| | - Paolo Curatolo
- Department of System Medicine, Child Neurology and Psychiatry Unit, Tor Vergata University Hospital, Rome, Italy
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Dietary GABA and its combination with vigabatrin mimic calorie restriction and induce antiobesity-like effects in lean mice. J Funct Foods 2021. [DOI: 10.1016/j.jff.2021.104367] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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The great barrier belief: The blood–brain barrier and considerations for juvenile toxicity studies. Reprod Toxicol 2017. [DOI: 10.1016/j.reprotox.2017.06.043] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Sousa K, Decker N, Pires TR, Papke DKM, Coelho VR, Pflüger P, Pereira P, Picada JN. Neurobehavioral effects of vigabatrin and its ability to induce DNA damage in brain cells after acute treatment in rats. Psychopharmacology (Berl) 2017; 234:129-136. [PMID: 27678549 DOI: 10.1007/s00213-016-4446-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 09/19/2016] [Indexed: 12/29/2022]
Abstract
RATIONALE Vigabatrin (VGB) is a drug indicated mostly for the treatment of spasms in childhood and West's syndrome patients. This drug inhibits irreversibly the enzyme GABA-transaminase (GABA-T), increasing GABA concentrations and enhancing GABAergic neurotransmission in the brain, which is known to induce behavioral changes. OBJECTIVES The aims of this study were to evaluate the effects of VGB in the short-term memory (STM), long-term memory (LTM), motivation, locomotion, and exploratory behavior tests and to detect deleterious or protective effects on DNA in target tissues of the drug. METHODS Male Wistar rats were treated with a single dose of VGB (100, 250, or 500 mg/kg) or saline solution before the inhibitory avoidance and open-field tasks. DNA damage was evaluated using the alkaline comet assay in peripheral blood, cerebral cortex, and hippocampus after behavioral testing. RESULTS There was no significant difference in the inhibitory avoidance task between the treated groups and the saline group. In all tested doses, VGB reduced the number of rearings in the open-field task. Besides, VGB 500 mg/kg affected locomotion, though it was not able to induce any DNA damage. CONCLUSIONS VGB did not affect STM and LTM, but the drug impaired the exploration and locomotion likely associated with its sedative effect. In addition, no DNA damage in cortex and hippocampus was detected after behavioral testing, when brain GABA levels are already increased.
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Affiliation(s)
- Karen Sousa
- Laboratory of Toxicological Genetics, Lutheran University of Brazil (ULBRA), Farroupilha Avenue, 8001, Canoas, RS, 2425-900, Brazil
| | - Natalia Decker
- Laboratory of Toxicological Genetics, Lutheran University of Brazil (ULBRA), Farroupilha Avenue, 8001, Canoas, RS, 2425-900, Brazil
| | - Thienne Rocha Pires
- Laboratory of Toxicological Genetics, Lutheran University of Brazil (ULBRA), Farroupilha Avenue, 8001, Canoas, RS, 2425-900, Brazil
| | - Débora Kuck Mausolff Papke
- Laboratory of Toxicological Genetics, Lutheran University of Brazil (ULBRA), Farroupilha Avenue, 8001, Canoas, RS, 2425-900, Brazil
| | - Vanessa Rodrigues Coelho
- Laboratory of Neuropharmacology and Pre-Clinical Toxicology. Pharmacology Department, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul (UFRGS), Sarmento Leite Street, 500/305, Porto Alegre, RS, 90050-170, Brazil
| | - Pricila Pflüger
- Laboratory of Neuropharmacology and Pre-Clinical Toxicology. Pharmacology Department, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul (UFRGS), Sarmento Leite Street, 500/305, Porto Alegre, RS, 90050-170, Brazil
| | - Patrícia Pereira
- Laboratory of Neuropharmacology and Pre-Clinical Toxicology. Pharmacology Department, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul (UFRGS), Sarmento Leite Street, 500/305, Porto Alegre, RS, 90050-170, Brazil
| | - Jaqueline Nascimento Picada
- Laboratory of Toxicological Genetics, Lutheran University of Brazil (ULBRA), Farroupilha Avenue, 8001, Canoas, RS, 2425-900, Brazil.
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Abstract
A pediatric assessment is now a required component of every drug marketing application in North America, Europe, and Japan, unless a waiver has been granted previously. Nonclinical juvenile toxicity studies are often required as part of this assessment. The protocols for juvenile toxicity studies are best devised in consultation with the regulatory authorities. It is important to submit the pediatric investigation plan (PIP) or pediatric study plan (PSP) early, in order not to delay the marketing authorization of the drug in adults. The choice of species and the design of juvenile toxicity studies are based on a series of complex considerations, including the therapeutic use of the drug, age at which children will be treated, duration of treatment, and potential age- or species-specific differences in efficacy, pharmacokinetics, or toxicity.
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Coelho VR, Sousa K, Pires TR, Papke DKM, Vieira CG, de Souza LP, Leal MB, Schunck RVA, Picada JN, Pereira P. Genotoxic and mutagenic effects of vigabatrin, a γ-aminobutyric acid transaminase inhibitor, in Wistar rats submitted to rotarod task. Hum Exp Toxicol 2016; 35:958-65. [DOI: 10.1177/0960327115611970] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Vigabatrin (VGB) is an antiepileptic drug thatincreases brain γ-aminobutyric acid (GABA) levels through irreversible inhibition of GABA transaminase. The aim of this study was to evaluate neurotoxicological effects of VGB measuring motor activity and genotoxic and mutagenic effects after a single and repeated administration. Male Wistar rats received saline, VGB 50, 100, or 250 mg/kg by gavage for acute and subchronic (14 days) treatments and evaluated in the rotarod task. Genotoxicity was evaluated using the alkaline version of the comet assay in samples of blood, liver, hippocampus, and brain cortex after both treatments. Mutagenicity was evaluated using the micronucleus test in bone marrow of the same animals that received subchronic treatment. The groups treated with VGB showed similar performance in rotarod compared with the saline group. Regarding the acute treatment, it was observed that only higher VGB doses induced DNA damage in blood and hippocampus. After the subchronic treatment, VGB did not show genotoxic or mutagenic effects. In brief, VGB did not impair motor activities in rats after acute and subchronic treatments. It showed a repairable genotoxic potential in the central nervous system since genotoxicity was observed in the acute treatment group.
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Affiliation(s)
- VR Coelho
- Laboratory of Neuropharmacology and Preclinical Toxicology, Department of Pharmacology, Institute of Basic Health Sciences, Federal University of Rio Grande doSul, Porto Alegre, Brazil
| | - K Sousa
- Laboratory of Genetic Toxicology, Lutheran University of Brazil, Canoas, Brazil
| | - TR Pires
- Laboratory of Genetic Toxicology, Lutheran University of Brazil, Canoas, Brazil
| | - DKM Papke
- Laboratory of Genetic Toxicology, Lutheran University of Brazil, Canoas, Brazil
| | - CG Vieira
- Laboratory of Neuropharmacology and Preclinical Toxicology, Department of Pharmacology, Institute of Basic Health Sciences, Federal University of Rio Grande doSul, Porto Alegre, Brazil
| | - LP de Souza
- Laboratory of Neuropharmacology and Preclinical Toxicology, Department of Pharmacology, Institute of Basic Health Sciences, Federal University of Rio Grande doSul, Porto Alegre, Brazil
| | - MB Leal
- Laboratory of Pharmacology and Toxicology of Natural Products, Department of Pharmacology, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - RVA Schunck
- Laboratory of Pharmacology and Toxicology of Natural Products, Department of Pharmacology, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - JN Picada
- Laboratory of Genetic Toxicology, Lutheran University of Brazil, Canoas, Brazil
| | - P Pereira
- Laboratory of Neuropharmacology and Preclinical Toxicology, Department of Pharmacology, Institute of Basic Health Sciences, Federal University of Rio Grande doSul, Porto Alegre, Brazil
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Bottomley AL, Rowles A, Mitchell DJ, Rasmussen AD. Detection of Mild and Reversible Neurohistopathological Changes in the Brain of Juvenile (Preweaned) Beagle Dogs Treated with Vigabatrin for up to 91 Days. Toxicol Pathol 2015; 43:1015-24. [PMID: 26157036 DOI: 10.1177/0192623315591838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Neurohistopathological changes in the brain were assessed in juvenile beagle dogs given vigabatrin at 30 or 100 mg/kg/day by oral gavage from postnatal day 22 (PND22) until 16 weeks of age (PND112), when brain myelination is considered to reach the adult stage in dogs. Separate subgroups were treated from PND22 to PND35 or PND36 to PND49 to assess early effects. In addition to extensive brain histopathology, there were assessments of toxicokinetics, clinical condition, body weight, organ weights, and macroscopic pathology. In animals treated for 14 days from PND22, minimal or slight vacuolation was seen in the neuropil of the septal nuclei, hippocampus, hypothalamus, thalamus, cerebellum, and globus pallidus at 100 mg/kg/day and minimal vacuolation in the thalamus, globus pallidus, and cerebellum at 30 mg/kg/day. In animals given 100 mg/kg/day for 91 days from PND22, minimal or slight vacuolation was observed only in the hippocampus, hypothalamus, and thalamus. No vigabatrin-related brain vacuolation was observed in animals given 30 or 100 mg/kg/day for 14 days from PND36. Clear evidence of recovery was observed after 14-day and 6-week off-dose periods that followed treatment from PND22 to PND35 or PND22 to PND112, respectively.
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Rasmussen AD, Richmond E, Wegener KM, Downes N, Mullins P. Vigabatrin-induced CNS changes in juvenile rats: Induction, progression and recovery of myelin-related changes. Neurotoxicology 2015; 46:137-44. [DOI: 10.1016/j.neuro.2014.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Revised: 12/09/2014] [Accepted: 12/19/2014] [Indexed: 11/16/2022]
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Butt AM, Fern RF, Matute C. Neurotransmitter signaling in white matter. Glia 2014; 62:1762-79. [PMID: 24753049 DOI: 10.1002/glia.22674] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 03/04/2014] [Accepted: 03/31/2014] [Indexed: 12/16/2022]
Abstract
White matter (WM) tracts are bundles of myelinated axons that provide for rapid communication throughout the CNS and integration in grey matter (GM). The main cells in myelinated tracts are oligodendrocytes and astrocytes, with small populations of microglia and oligodendrocyte precursor cells. The prominence of neurotransmitter signaling in WM, which largely exclude neuronal cell bodies, indicates it must have physiological functions other than neuron-to-neuron communication. A surprising aspect is the diversity of neurotransmitter signaling in WM, with evidence for glutamatergic, purinergic (ATP and adenosine), GABAergic, glycinergic, adrenergic, cholinergic, dopaminergic and serotonergic signaling, acting via a wide range of ionotropic and metabotropic receptors. Both axons and glia are potential sources of neurotransmitters and may express the respective receptors. The physiological functions of neurotransmitter signaling in WM are subject to debate, but glutamate and ATP-mediated signaling have been shown to evoke Ca(2+) signals in glia and modulate axonal conduction. Experimental findings support a model of neurotransmitters being released from axons during action potential propagation acting on glial receptors to regulate the homeostatic functions of astrocytes and myelination by oligodendrocytes. Astrocytes also release neurotransmitters, which act on axonal receptors to strengthen action potential propagation, maintaining signaling along potentially long axon tracts. The co-existence of multiple neurotransmitters in WM tracts suggests they may have diverse functions that are important for information processing. Furthermore, the neurotransmitter signaling phenomena described in WM most likely apply to myelinated axons of the cerebral cortex and GM areas, where they are doubtless important for higher cognitive function.
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Affiliation(s)
- Arthur M Butt
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, United Kingdom
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Baldrick P. The evolution of juvenile animal testing for small and large molecules. Regul Toxicol Pharmacol 2013; 67:125-35. [DOI: 10.1016/j.yrtph.2013.07.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 07/19/2013] [Indexed: 11/25/2022]
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