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Steele JW, Krishnan V, Finnell RH. Mechanisms of neurodevelopmental toxicity of topiramate. Crit Rev Toxicol 2024; 54:465-475. [PMID: 38995641 PMCID: PMC11296906 DOI: 10.1080/10408444.2024.2368552] [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: 02/27/2024] [Revised: 05/03/2024] [Accepted: 06/11/2024] [Indexed: 07/13/2024]
Abstract
Prescriptions for antiseizure medications (ASMs) have been rapidly growing over the last several decades due, in part, to an expanding list of clinical indications for which they are now prescribed. This trend has raised concern for potential adverse neurodevelopmental outcomes in ASM-exposed pregnancies. Recent large scale population studies have suggested that the use of topiramate (TOPAMAX, Janssen-Cilag), when prescribed for seizure control, migraines, and/or weight management, is associated with an increased risk for autism spectrum disorder (ASD), intellectual disability, and attention-deficit/hyperactivity disorder (ADHD) in exposed offspring. Here, we critically review epidemiologic evidence demonstrating the neurobehavioral teratogenicity of topiramate and speculate on the neuromolecular mechanisms by which prenatal exposure may perturb neurocognitive development. Specifically, we explore the potential role of topiramate's pharmacological interactions with ligand- and voltage-gated ion channels, especially GABAergic signaling, its effects on DNA methylation and histone acetylation, whether topiramate induces oxidative stress, and its association with fetal growth restriction as possible mechanisms contributing to neurodevelopmental toxicity. Resolving this biology will be necessary to reduce the risk of adverse pregnancy outcomes caused by topiramate or other ASMs.
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Affiliation(s)
- John W. Steele
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, TX, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Vaishnav Krishnan
- Departments of Neurology, Neuroscience and Psychiatry, and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA
| | - Richard H. Finnell
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, TX, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA
- Departments of Molecular and Cellular Biology and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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Warm D, Schroer J, Sinning A. Gabaergic Interneurons in Early Brain Development: Conducting and Orchestrated by Cortical Network Activity. Front Mol Neurosci 2022; 14:807969. [PMID: 35046773 PMCID: PMC8763242 DOI: 10.3389/fnmol.2021.807969] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/06/2021] [Indexed: 01/22/2023] Open
Abstract
Throughout early phases of brain development, the two main neural signaling mechanisms—excitation and inhibition—are dynamically sculpted in the neocortex to establish primary functions. Despite its relatively late formation and persistent developmental changes, the GABAergic system promotes the ordered shaping of neuronal circuits at the structural and functional levels. Within this frame, interneurons participate first in spontaneous and later in sensory-evoked activity patterns that precede cortical functions of the mature brain. Upon their subcortical generation, interneurons in the embryonic brain must first orderly migrate to and settle in respective target layers before they can actively engage in cortical network activity. During this process, changes at the molecular and synaptic level of interneurons allow not only their coordinated formation but also the pruning of connections as well as excitatory and inhibitory synapses. At the postsynaptic site, the shift of GABAergic signaling from an excitatory towards an inhibitory response is required to enable synchronization within cortical networks. Concomitantly, the progressive specification of different interneuron subtypes endows the neocortex with distinct local cortical circuits and region-specific modulation of neuronal firing. Finally, the apoptotic process further refines neuronal populations by constantly maintaining a controlled ratio of inhibitory and excitatory neurons. Interestingly, many of these fundamental and complex processes are influenced—if not directly controlled—by electrical activity. Interneurons on the subcellular, cellular, and network level are affected by high frequency patterns, such as spindle burst and gamma oscillations in rodents and delta brushes in humans. Conversely, the maturation of interneuron structure and function on each of these scales feeds back and contributes to the generation of cortical activity patterns that are essential for the proper peri- and postnatal development. Overall, a more precise description of the conducting role of interneurons in terms of how they contribute to specific activity patterns—as well as how specific activity patterns impinge on their maturation as orchestra members—will lead to a better understanding of the physiological and pathophysiological development and function of the nervous system.
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Erisgin Z, Ayas B, Nyengaard JR, Ercument Beyhun N, Terzi Y. The neurotoxic effects of prenatal gabapentin and oxcarbazepine exposure on newborn rats. J Matern Fetal Neonatal Med 2017; 32:461-471. [PMID: 28931341 DOI: 10.1080/14767058.2017.1383378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
AIM Teratogenicity is a problematic issue for pregnant women because of X-ray radiation, drugs, and genetic and unknown variables. First-generation antiepileptic drugs (AED) like valproic acid are well-known teratogens for developing fetuses. However, their usage is necessary in order to prevent maternal seizures. The underlying mechanism of birth defects associated with AED exposure remains unclear and information about the neurotoxic effects of prenatal exposure to AED is still limited. Oxcarbazepine (OXC) and gabapentin (GBP) are second-generation AED. It still remains unclear how much these drugs are safe during pregnancy. This study aimed to investigate whether any neurotoxic effect of OXC and GBP in utero exposure on the developing brain. METHODS Eighteen pregnant Wistar albino rats were divided into six groups. The first group was exposed to OXC at 100 mg/kg/day, the second to GBP at 50 mg/kg/day, and third to saline (0.9% NaCl) at 1.5 ml/day between the first and the fifth days of gestation. The same procedure was applied at the same dosages between the 6th and the 15th days of gestation for the 2nd three groups. Five female offspring (total n = 30, 45 days old) were taken from each group and stereological methods were applied in order to analyze the total and dopaminergic neuron number of the substantia nigra pars compacta (SNc). CONCLUSION The result is that the OXC and GBP exposure at different gestational periods may not give rise to congenital malformation and it appears that the GBP exposure during the organogenesis period proliferatively affects the total number of neurons.
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Affiliation(s)
- Zuleyha Erisgin
- a Department of Histology and Embryology , Giresun University, Faculty of Medicine , Giresun , Turkey
| | - Bulent Ayas
- b Department of Histology and Embryology , Ondokuz Mayıs University, Faculty of Medicine , Samsun , Turkey
| | - Jens R Nyengaard
- c Stereology and Electron Microscopy Laboratory , Aarhus University Hospital , Aarhus , Denmark
| | - N Ercument Beyhun
- d Department of Public Health , Black Sea Technical University, Faculty of Medicine , Trabzon , Turkey
| | - Yuksel Terzi
- e Department of Statistic, Faculty of Fine and Art , Ondokuz Mayıs University , Samsun , Turkey
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Kilb W, Kirischuk S, Luhmann HJ. Role of tonic GABAergic currents during pre- and early postnatal rodent development. Front Neural Circuits 2013; 7:139. [PMID: 24027498 PMCID: PMC3760143 DOI: 10.3389/fncir.2013.00139] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/16/2013] [Indexed: 11/13/2022] Open
Abstract
In the last three decades it became evident that the GABAergic system plays an essential role for the development of the central nervous system, by influencing the proliferation of neuronal precursors, neuronal migration and differentiation, as well as by controlling early activity patterns and thus formation of neuronal networks. GABA controls neuronal development via depolarizing membrane responses upon activation of ionotropic GABA receptors. However, many of these effects occur before the onset of synaptic GABAergic activity and thus require the presence of extrasynaptic tonic currents in neuronal precursors and immature neurons. This review summarizes our current knowledge about the role of tonic GABAergic currents during early brain development. In this review we compare the temporal sequence of the expression and functional relevance of different GABA receptor subunits, GABA synthesizing enzymes and GABA transporters. We also refer to other possible endogenous agonists of GABAA receptors. In addition, we describe functional consequences mediated by the GABAergic system during early developmental periods and discuss current models about the origin of extrasynaptic GABA and/or other endogenous GABAergic agonists during early developmental states. Finally, we present evidence that tonic GABAergic activity is also critically involved in the generation of physiological as well as pathophysiological activity patterns before and after the establishment of functional GABAergic synaptic connections.
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Affiliation(s)
- Werner Kilb
- Institute of Physiology and Pathophysiology, University Medical Center, Johannes Gutenberg University Mainz, Germany
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D'Arrigo A, Colavito D, Peña-Altamira E, Fabris M, Dam M, Contestabile A, Leon A. Transcriptional profiling in the lumbar spinal cord of a mouse model of amyotrophic lateral sclerosis: a role for wild-type superoxide dismutase 1 in sporadic disease? J Mol Neurosci 2010; 41:404-15. [PMID: 20177826 DOI: 10.1007/s12031-010-9332-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 01/14/2010] [Indexed: 02/06/2023]
Abstract
Mice bearing mutations of copper-zinc-superoxide dismutase recapitulate spinal cord motor neuron degeneration and disease progression occurring in human amyotrophic lateral sclerosis. We have investigated the relationship between disease progression and altered gene expression by comparing the transcriptional profiles in lumbar spinal cord, fronto-parietal cortex and hippocampus of mutant G93A-SOD1, wild-type SOD1 transgenic and non-transgenic mice. Gene expression was evaluated at 55 and 110 days of age, representing pre-symptomatic and advanced disease stages of G93A mice, respectively. Whereas no significant variations were detectable in cortical and hippocampal areas, several mutation-related changes were detected in the lumbar spinal cord at the symptomatic stage, consistent with a condition of neuronal distress. Also, at both ages, we found a number of transgene-related changes, i.e. variations occurring in both transgenic groups independently of the G93A mutation, with wild-type SOD1- and G93A-SOD1-overexpressing mice displaying global transcriptional similarity at 110 days of age. Some of the changes in common between the two transgenic groups involve genes implicated in oxidative stress, inflammation, spinocerebellar degeneration and other neurodegenerative disorders. The finding that gene expressional alterations potentially associated to cellular distress are shared by wild-type and mutant human SOD1-overexpressing mice raises the possibility that mutated (in familial ALS) or otherwise dysregulated (in sporadic ALS) SOD1 expression is a common pathogenetic substrate of the disease.
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Lee HY, Naha N, Li SP, Jo MJ, Naseer MI, Naseer ML, Park MS, Park TJ, Chung BC, Kim MO. In vivo and in vitro ethanol exposure in prenatal rat brain: GABA(B) receptor modulation on dopamine D(1) receptor and protein kinase A. Synapse 2008; 62:534-43. [PMID: 18435423 DOI: 10.1002/syn.20522] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have investigated the effects of prenatal ethanol exposure on GABA(B) receptors (GABA(B)Rs), protein kinase A (PKA), and DA D(1) receptor (DAD(1)R) expressions. GABA(B1)R and GABA(B2)R showed different age-dependent expressions in in vivo fetal rat forebrain from gestational days (GD) 15.5 to 21.5 upon 10% ethanol treatment to mother, with and without baclofen at a dose of 10 mg/kg body weight/day. The protein level changes could not be attributed to changes in the level of transcription since GABA(B)R mRNA presented different expression patterns upon in vivo ethanol treatment. Using in vitro cultivated cortical neurons from GD 17.5 fetuses, we also explored the modulatory effects of ethanol on PKA and DAD(1)R through GABA(B)Rs, under 50 microM baclofen and 100 microM phaclofen administrations, with or without 100 mM of ethanol treatment in the culture media. The results showed that 20 min ethanol treatment without baclofen or phaclofen had increasing effects on both the GABA(B)Rs. Further, baclofen and phaclofen administration significantly affected PKA and GABA(B)R levels upon 20 min and 1 h ethanol treatment. In contrast, DAD(1)R showed increasing effects upon ethanol treatment, which was modulated by GABA(B)R's agonist baclofen and antagonist phaclofen. Therefore the present study suggested that the GABA(B)R activity could modulate ethanol's cellular effects, which possibly including PKA and DAD(1)R activities, and may be an underlying cause of ethanol's effects.
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Affiliation(s)
- H Y Lee
- Division of Life Science, College of Natural Sciences and Applied Life Science (Brain Korea 21), Gyeongsang National University, Chinju 660-701, South Korea
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Aronica E, Redeker S, Boer K, Spliet WGM, van Rijen PC, Gorter JA, Troost D. Inhibitory networks in epilepsy-associated gangliogliomas and in the perilesional epileptic cortex. Epilepsy Res 2007; 74:33-44. [PMID: 17267178 DOI: 10.1016/j.eplepsyres.2006.12.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2006] [Revised: 11/17/2006] [Accepted: 12/19/2006] [Indexed: 01/12/2023]
Abstract
Developmental glioneuronal lesions, such as gangliogliomas (GG) are increasingly recognized causes of chronic pharmaco-resistant epilepsy. It has been postulated that chronic epilepsy in patients with malformations of cortical development is associated with dysfunction of the inhibitory GABA-ergic system. We aimed to identify the subtypes of interneurons present within GG specimens and the expression and cellular distribution patterns of GABA receptors (GABAR) and GABA transporter 1 (GAT1). The expression of the various components of the GABA-ergic system were also analyzed in the perilesional cortex. We investigated the expression of parvalbumin, calbindin, calretinin, GABA(A)R (a1 subunit)(,) GABA(B) (R1 and R2) and GAT-1 using immunocytochemistry in 30 specimens of GG obtained during epilepsy surgery, including 10 cases with sufficient amount of perilesional cortex. Immunocytochemistry for calbindin (CB), calretinin (CR) and parvalbumin (PV) demonstrate the presence of inhibitory neurons of different subtypes within the GG specimens. Calcium-binding protein-positive interneurons represent a small fraction of the total neuronal population. Both GABA(A)R and GABA(B)R (R1 and R2) subtypes were detected within the neuronal component of GG specimens. In addition, GABA(B)R2 immunoreactivity (IR) was observed in glial cells. GG specimens displayed also expression of GAT-1 IR. Compared to normal cortex, the density of PV- and CB-immunoreactive interneurons was reduced in the perilesional cortex of GG patients, whereas CR-labeling was similar to that observed in normal cortex. GAT-1 IR was also significantly reduced in the perilesional specimens. The cellular distribution of components of the GABA-ergic system in GG, together with the perilesional changes suggest that alterations of the GABA-ergic system may contribute to the complex abnormal functional network of these highly epileptogenic developmental lesions.
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Affiliation(s)
- E Aronica
- Department of (Neuro) Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
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Robinson S, Li Q, Dechant A, Cohen ML. Neonatal loss of gamma-aminobutyric acid pathway expression after human perinatal brain injury. J Neurosurg 2006; 104:396-408. [PMID: 16776375 PMCID: PMC1762128 DOI: 10.3171/ped.2006.104.6.396] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Perinatal brain injury leads to chronic neurological deficits in children. Damage to the premature brain produces white matter lesions (WMLs), but the impact on cortical development is less well defined. Gamma-aminobutyric acid(GABA)ergic neurons destined for the cerebral cortex migrate through the developing white matter and form the subplate during late gestation. The authors hypothesized that GABAergic neurons are vulnerable to perinatal systemic insults in premature infants, and that damage to these neurons contributes to impaired cortical development. METHODS An immunohistochemical analysis involving markers for oligodendrocytes, GABAergic neurons, axons, and apoptosis was performed on a consecutive series of 15 human neonatal telencephalon samples obtained postmortem from infants born at 25 to 32 weeks of gestation. The tissue samples were divided into two groups based on the presence or absence of WMLs by performing routine histological analyses. The expression of GABAergic neurons was compared between the two groups by using age-matched samples. Two-tailed t-tests were used for statistical analyses. Ten infants had WMLs and five did not. Significant losses of oligodendrocytes and axons and markedly increased apoptosis were appreciated in tissue samples from the infants with WMLs. Samples from infants with WMLs also showed significant losses of glutamic acid decarboxylase-67-positive cells and calretinin-positive cells, shorter neuropeptide Y-positive neurite lengths, and losses of cells expressing GABA(A)alpha1, GABA(B)R1, and N-acetylaspartate diethylamide NR1 receptors when these factors were compared with those in samples from infants without WMLs (all p < 0.02). CONCLUSIONS In addition to oligodendrocyte loss, axonal disruption, and excess apoptosis, a significant loss of telencephalon GABAergic neuron expression was found in neonatal brains with WMLs, compared with neonates' brains without WMLs. The loss of GABAergic subplate neurons in infants with WMLs may contribute to the pathogenesis of neurological deficits in children.
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Affiliation(s)
- Shenandoah Robinson
- Department of Neurosurgery, Division of Neuropathology, University Hospitals of Cleveland, Case Research Institute, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA.
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Neto FL, Ferreira-Gomes J, Castro-Lopes JM. Distribution of GABA Receptors in the Thalamus and Their Involvement in Nociception. GABA 2006; 54:29-51. [PMID: 17175809 DOI: 10.1016/s1054-3589(06)54002-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Fani L Neto
- Institute of Histology and Embryology, Faculty of Medicine of Porto and IBMC, 4200-319 Porto, Portugal
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Rout UK. Alcohol, GABA receptors, and neurodevelopmental disorders. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2005; 71:217-37. [PMID: 16512353 DOI: 10.1016/s0074-7742(05)71010-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Ujjwal K Rout
- Department of Surgery, Division of Pediatric Surgery, Research Laboratories University of Mississippi Medical Center, Jackson 39216, USA
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