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Goikolea-Vives A, Fernandes C, Thomas MSC, Thornton C, Stolp HB. Sex-specific behavioural deficits in adulthood following acute activation of the GABAA receptor in the neonatal mouse. Dev Neurosci 2024:000536641. [PMID: 38325353 DOI: 10.1159/000536641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 01/26/2024] [Indexed: 02/09/2024] Open
Abstract
INTRODUCTION Sex differences exist in the prevalence of neurodevelopmental disorders (NDDs). Part of the aetiology of NDDs has been proposed to be alterations in the balance between excitatory and inhibitory neurotransmission, leading to the question of whether males and females respond differently to altered neurotransmitter balance. We investigated whether pharmacological alteration of GABAA signalling in early development results in sex-dependent changes in adult behaviours associated with NDDs. METHODS Male and female C57BL/6J mice received intraperitoneal injections of 0.5mg/kg muscimol or saline on postnatal days (P) 3-5 and were subjected to behavioural testing, specifically open field, light dark box, marble burying, sucralose preference, social interaction and olfactory habituation/dishabituation tests between P60-90. RESULTS Early postnatal administration of muscimol resulted in reduced anxiety in the light dark box test in both male and female adult mice. Muscimol reduced sucralose preference in males, but not females, whereas female mice showed reduced social behaviours. Regional alterations in cortical thickness were observed in the weeks following GABAA receptor activation, pointing to an evolving structural difference in the brain underlying adult behaviour. CONCLUSIONS We conclude that activation of the GABAA receptor in the first week of life resulted in long-lasting changes in a range of behaviours in adulthood following altered neurodevelopment. Sex of the individual affected the nature and severity of these abnormalities, explaining part of the varied pathophysiology and neurodevelopmental diagnosis that derive from excitatory/inhibitory imbalance.
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Tahara M, Higurashi N, Hata J, Nishikawa M, Ito K, Hirose S, Kaneko T, Mashimo T, Sakuma T, Yamamoto T, Okano HJ. Developmental changes in brain activity of heterozygous Scn1a knockout rats. Front Neurol 2023; 14:1125089. [PMID: 36998780 PMCID: PMC10043303 DOI: 10.3389/fneur.2023.1125089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/20/2023] [Indexed: 03/17/2023] Open
Abstract
IntroductionDravet syndrome (DS) is an infantile-onset developmental and epileptic encephalopathy characterized by an age-dependent evolution of drug-resistant seizures and poor developmental outcomes. Functional impairment of gamma-aminobutyric acid (GABA)ergic interneurons due to loss-of-function mutation of SCN1A is currently considered the main pathogenesis. In this study, to better understand the age-dependent changes in the pathogenesis of DS, we characterized the activity of different brain regions in Scn1a knockout rats at each developmental stage.MethodsWe established an Scn1a knockout rat model and examined brain activity from postnatal day (P) 15 to 38 using a manganese-enhanced magnetic resonance imaging technique (MEMRI).ResultsScn1a heterozygous knockout (Scn1a+/−) rats showed a reduced expression of voltage-gated sodium channel alpha subunit 1 protein in the brain and heat-induced seizures. Neural activity was significantly higher in widespread brain regions of Scn1a+/− rats than in wild-type rats from P19 to P22, but this difference did not persist thereafter. Bumetanide, a Na+-K+-2Cl− cotransporter 1 inhibitor, mitigated hyperactivity to the wild-type level, although no change was observed in the fourth postnatal week. Bumetanide also increased heat-induced seizure thresholds of Scn1a+/− rats at P21.ConclusionsIn Scn1a+/− rats, neural activity in widespread brain regions increased during the third postnatal week, corresponding to approximately 6 months of age in humans, when seizures most commonly develop in DS. In addition to impairment of GABAergic interneurons, the effects of bumetanide suggest a possible contribution of immature type A gamma-aminobutyric acid receptor signaling to transient hyperactivity and seizure susceptibility during the early stage of DS. This hypothesis should be addressed in the future. MEMRI is a potential technique for visualizing changes in basal brain activity in developmental and epileptic encephalopathies.
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Affiliation(s)
- Mayu Tahara
- Department of Pediatrics, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
- Division of Regenerative Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Norimichi Higurashi
- Department of Pediatrics, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
- *Correspondence: Norimichi Higurashi
| | - Junichi Hata
- Division of Regenerative Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
- Graduate School of Human Health Sciences, Tokyo Metropolitan University, Arakawa-ku, Tokyo, Japan
| | - Masako Nishikawa
- Clinical Research Support Center, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Ken Ito
- Department of Pediatrics, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
- Division of Regenerative Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Shinichi Hirose
- General Medical Research Center, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Takehito Kaneko
- Division of Fundamental and Applied Sciences, Graduate School of Science and Engineering, Iwate University, Morioka, Japan
| | - Tomoji Mashimo
- Division of Animal Genetics, Laboratory Animal Research Center, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo, Japan
| | - Tetsushi Sakuma
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Takashi Yamamoto
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Hirotaka James Okano
- Division of Regenerative Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
- Hirotaka James Okano
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Hui KK, Chater TE, Goda Y, Tanaka M. How Staying Negative Is Good for the (Adult) Brain: Maintaining Chloride Homeostasis and the GABA-Shift in Neurological Disorders. Front Mol Neurosci 2022; 15:893111. [PMID: 35875665 PMCID: PMC9305173 DOI: 10.3389/fnmol.2022.893111] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/10/2022] [Indexed: 01/27/2023] Open
Abstract
Excitatory-inhibitory (E-I) imbalance has been shown to contribute to the pathogenesis of a wide range of neurodevelopmental disorders including autism spectrum disorders, epilepsy, and schizophrenia. GABA neurotransmission, the principal inhibitory signal in the mature brain, is critically coupled to proper regulation of chloride homeostasis. During brain maturation, changes in the transport of chloride ions across neuronal cell membranes act to gradually change the majority of GABA signaling from excitatory to inhibitory for neuronal activation, and dysregulation of this GABA-shift likely contributes to multiple neurodevelopmental abnormalities that are associated with circuit dysfunction. Whilst traditionally viewed as a phenomenon which occurs during brain development, recent evidence suggests that this GABA-shift may also be involved in neuropsychiatric disorders due to the “dematuration” of affected neurons. In this review, we will discuss the cell signaling and regulatory mechanisms underlying the GABA-shift phenomenon in the context of the latest findings in the field, in particular the role of chloride cotransporters NKCC1 and KCC2, and furthermore how these regulatory processes are altered in neurodevelopmental and neuropsychiatric disorders. We will also explore the interactions between GABAergic interneurons and other cell types in the developing brain that may influence the GABA-shift. Finally, with a greater understanding of how the GABA-shift is altered in pathological conditions, we will briefly outline recent progress on targeting NKCC1 and KCC2 as a therapeutic strategy against neurodevelopmental and neuropsychiatric disorders associated with improper chloride homeostasis and GABA-shift abnormalities.
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Affiliation(s)
- Kelvin K. Hui
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, United States
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY, United States
- *Correspondence: Kelvin K. Hui,
| | - Thomas E. Chater
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
- Thomas E. Chater,
| | - Yukiko Goda
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
- Synapse Biology Unit, Okinawa Institute for Science and Technology Graduate University, Onna, Japan
| | - Motomasa Tanaka
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Japan
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NKCC1 Deficiency in Forming Hippocampal Circuits Triggers Neurodevelopmental Disorder: Role of BDNF-TrkB Signalling. Brain Sci 2022; 12:brainsci12040502. [PMID: 35448033 PMCID: PMC9030861 DOI: 10.3390/brainsci12040502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 04/06/2022] [Accepted: 04/12/2022] [Indexed: 12/10/2022] Open
Abstract
The time-sensitive GABA shift from excitatory to inhibitory is critical in early neural circuits development and depends upon developmentally regulated expression of cation-chloride cotransporters NKCC1 and KCC2. NKCC1, encoded by the SLC12A2 gene, regulates neuronal Cl− homeostasis by chloride import working opposite KCC2. The high NKCC1/KCC2 expression ratio decreases in early neural development contributing to GABA shift. Human SLC12A2 loss-of-function mutations were recently associated with a multisystem disorder affecting neural development. However, the multisystem phenotype of rodent Nkcc1 knockout models makes neurodevelopment challenging to study. Brain-Derived Neurotrophic Factor (BDNF)-NTRK2/TrkB signalling controls KCC2 expression during neural development, but its impact on NKCC1 is still controversial. Here, we discuss recent evidence supporting BDNF-TrkB signalling controlling Nkcc1 expression and the GABA shift during hippocampal circuit formation. Namely, specific deletion of Ntrk2/Trkb from immature mouse hippocampal dentate granule cells (DGCs) affects their integration and maturation in the hippocampal circuitry and reduces Nkcc1 expression in their target region, the CA3 principal cells, leading to premature GABA shift, ultimately influencing the establishment of functional hippocampal circuitry and animal behaviour in adulthood. Thus, immature DGCs emerge as a potential therapeutic target as GABAergic transmission is vital for specific neural progenitors generating dentate neurogenesis in early development and the mature brain.
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Sex-specific differences in KCC2 localisation and inhibitory synaptic transmission in the rat hippocampus. Sci Rep 2022; 12:3186. [PMID: 35210456 PMCID: PMC8873453 DOI: 10.1038/s41598-022-06769-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 02/03/2022] [Indexed: 11/09/2022] Open
Abstract
Sexual differentiation of the brain is influenced by testosterone and its metabolites during the perinatal period, when many aspects of brain development, including the maturation of GABAergic transmission, occur. Whether and how testosterone signaling during the perinatal period affects GABAergic transmission is unclear. Here, we analyzed GABAergic circuit functional markers in male, female, testosterone-treated female, and testosterone-insensitive male rats after the first postnatal week and in young adults. In the hippocampus, mRNA levels of proteins associated with GABA signaling were not significantly affected at postnatal day (P) 7 or P40. Conversely, membrane protein levels of KCC2, which are critical for determining inhibition strength, were significantly higher in females compared to males and testosterone-treated females at P7. Further, female and testosterone-insensitive male rats at P7 showed higher levels of the neurotrophin BDNF, which is a powerful regulator of neuronal function, including GABAergic transmission. Finally, spontaneous GABAergic currents in hippocampal CA1 pyramidal cells were more frequent in females and testosterone-insensitive males at P40. Overall, these results show that perinatal testosterone levels modulate GABAergic circuit function, suggesting a critical role of perinatal sex hormones in regulating network excitability in the adult hippocampus.
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Peerboom C, Wierenga CJ. The postnatal GABA shift: A developmental perspective. Neurosci Biobehav Rev 2021; 124:179-192. [PMID: 33549742 DOI: 10.1016/j.neubiorev.2021.01.024] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 01/13/2021] [Accepted: 01/28/2021] [Indexed: 12/13/2022]
Abstract
GABA is the major inhibitory neurotransmitter that counterbalances excitation in the mature brain. The inhibitory action of GABA relies on the inflow of chloride ions (Cl-), which hyperpolarizes the neuron. In early development, GABA signaling induces outward Cl- currents and is depolarizing. The postnatal shift from depolarizing to hyperpolarizing GABA is a pivotal event in brain development and its timing affects brain function throughout life. Altered timing of the postnatal GABA shift is associated with several neurodevelopmental disorders. Here, we argue that the postnatal shift from depolarizing to hyperpolarizing GABA represents the final shift in a sequence of GABA shifts, regulating proliferation, migration, differentiation, and finally plasticity of developing neurons. Each developmental GABA shift ensures that the instructive role of GABA matches the circumstances of the developing network. Sensory input may be a crucial factor in determining proper timing of the postnatal GABA shift. A developmental perspective is necessary to interpret the full consequences of a mismatch between connectivity, activity and GABA signaling during brain development.
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Affiliation(s)
- Carlijn Peerboom
- Cell Biology, Neurobiology and Biophysics, Biology Department, Faculty of Science, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Corette J Wierenga
- Cell Biology, Neurobiology and Biophysics, Biology Department, Faculty of Science, Utrecht University, 3584 CH, Utrecht, the Netherlands.
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Pisani F, Fusco C, Spagnoli C. Linking acute symptomatic neonatal seizures, brain injury and outcome in preterm infants. Epilepsy Behav 2020; 112:107406. [PMID: 32889509 DOI: 10.1016/j.yebeh.2020.107406] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/06/2020] [Accepted: 08/09/2020] [Indexed: 11/29/2022]
Abstract
Neonatal seizures (NS) are the most frequent sign of neurological dysfunction in newborn infants. With increased survival of preterm neonates, the current clinical focus has shifted from preventing death to improving long-term neurological outcome. In the context of acute symptomatic NS, the main negative prognostic factors include etiology, and severity of brain injury, but also prolonged seizures and especially status epilepticus. However, the reasons for the detrimental contribution of seizures to outcome are still unclear, and evidence has been collected both in favor of seizures being an epiphenomenon of brain injury and of independently contributing to further damage. In this narrative focused review, we will discuss both hypotheses, with special emphasis on data relating to preterm infants. We will also identify present controversies and possible future lines of research.
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Affiliation(s)
- Francesco Pisani
- Child Neuropsychiatric Unit, Medicine & Surgery Department, Neuroscience Section, University of Parma, Italy.
| | - Carlo Fusco
- Department of Pediatrics, Child Neurology Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy.
| | - Carlotta Spagnoli
- Department of Pediatrics, Child Neurology Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy.
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8
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Molinero I, Galanopoulou AS, Moshé SL. Rodent models: Where it all started with these "truths". Eur J Paediatr Neurol 2020; 24:61-65. [PMID: 31875833 PMCID: PMC7179510 DOI: 10.1016/j.ejpn.2019.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 12/06/2019] [Indexed: 01/23/2023]
Affiliation(s)
- Isaac Molinero
- Isabelle Rapin Division of Child Neurology and Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, and Comprehensive Einstein/Montefiore Epilepsy Center, Albert Einstein College of Medicine, Bronx, NY, 10467, USA; 111 East 210th Street, Montefiore Medical Center, Bronx, NY, 10467, USA.
| | - Aristea S Galanopoulou
- Isabelle Rapin Division of Child Neurology and Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, and Comprehensive Einstein/Montefiore Epilepsy Center, Albert Einstein College of Medicine, Bronx, NY, 10467, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; 1410 Pelham Parkway South, Kennedy Center Rm 306, Bronx, NY, 10461, USA.
| | - Solomon L Moshé
- Isabelle Rapin Division of Child Neurology and Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, and Comprehensive Einstein/Montefiore Epilepsy Center, Albert Einstein College of Medicine, Bronx, NY, 10467, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; 1410 Pelham Parkway South, Kennedy Center Rm 316, Bronx, NY, 10461, USA.
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9
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Arambula SE, Reinl EL, El Demerdash N, McCarthy MM, Robertson CL. Sex differences in pediatric traumatic brain injury. Exp Neurol 2019; 317:168-179. [PMID: 30831070 DOI: 10.1016/j.expneurol.2019.02.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 02/21/2019] [Accepted: 02/28/2019] [Indexed: 02/08/2023]
Abstract
The response of the developing brain to traumatic injury is different from the response of the mature, adult brain. There are critical developmental trajectories in the young brain, whereby injury can lead to long term functional abnormalities. Emerging preclinical and clinical literature supports the presence of significant sex differences in both the response to and the recovery from pediatric traumatic brain injury (TBI). These sex differences are seen at all pediatric ages, including neonates/infants, pre-pubertal children, and adolescents. As importantly, the response to neuroprotective therapies or treatments can differ between male and females subjects. These sex differences can result from several biologic origins, and may manifest differently during the various phases of brain and body development. Recognizing and understanding these potential sex differences is crucial, and should be considered in both preclinical and clinical studies of pediatric TBI.
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Affiliation(s)
- Sheryl E Arambula
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Erin L Reinl
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Nagat El Demerdash
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Margaret M McCarthy
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Courtney L Robertson
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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10
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Rezzani R, Franco C, Rodella LF. Sex differences of brain and their implications for personalized therapy. Pharmacol Res 2019; 141:429-442. [PMID: 30659897 DOI: 10.1016/j.phrs.2019.01.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/14/2019] [Accepted: 01/15/2019] [Indexed: 01/06/2023]
Abstract
Nowadays, it is known that the sex differences regard many organs, e.g., liver, vessels, pancreas, lungs, bronchi and also the brain. Sex differences are not just a matter of ethical and moral principles, as they are central to explain many still unknown diseases and their understanding is a prerequisite to develop an effective therapy for each individual. This review reports on those sex differences that are not only macroscopic and morphological, but also involve molecular and functional dimorphism in the brain. It will recapitulate the main structural differences between male and female brain including the neurotransmission systems; in particular, the main objective is to identify a correlation, already known or to be investigated in the future, between the differences that characterize male and female brains from a morphological and biochemical point of view and neurological syndromes. This correlation could provide a starting point for future scientific research aimed to investigate and define a personalized therapy.
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Affiliation(s)
- Rita Rezzani
- Anatomy and Physiopathology Division, Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11, 25123 Brescia, Italy; Interdipartimental University Center of Research "Adaption and Regeneration of Tissues and Organs-(ARTO)", University of Brescia, 25123 Brescia, Italy.
| | - Caterina Franco
- Anatomy and Physiopathology Division, Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Luigi F Rodella
- Anatomy and Physiopathology Division, Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11, 25123 Brescia, Italy; Interdipartimental University Center of Research "Adaption and Regeneration of Tissues and Organs-(ARTO)", University of Brescia, 25123 Brescia, Italy
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11
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Chung BYT, Bailey CDC. Sex differences in the nicotinic excitation of principal neurons within the developing hippocampal formation. Dev Neurobiol 2018; 79:110-130. [PMID: 30354016 DOI: 10.1002/dneu.22646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 10/15/2018] [Accepted: 10/17/2018] [Indexed: 12/21/2022]
Abstract
The hippocampal formation (HF) plays an important role to facilitate higher order cognitive functions. Cholinergic activation of heteromeric nicotinic acetylcholine receptors (nAChRs) within the HF is critical for the normal development of principal neurons within this brain region. However, previous research investigating the expression and function of heteromeric nAChRs in principal neurons of the HF is limited to males or does not differentiate between the sexes. We used whole-cell electrophysiology to show that principal neurons in the CA1 region of the female mouse HF are excited by heteromeric nAChRs throughout postnatal development, with the greatest response occurring during the first two weeks of postnatal life. Excitability responses to heteromeric nAChR stimulation were also found in principal neurons in the CA3, dentate gyrus, subiculum, and entorhinal cortex layer VI (ECVI) of young postnatal female HF. A direct comparison between male and female mice found that principal neurons in ECVI display greater heteromeric nicotinic passive and active excitability responses in females. This sex difference is likely influenced by the generally more excitable nature of ECVI neurons from female mice, which display a higher resting membrane potential, greater input resistance, and smaller afterhyperpolarization potential of medium duration (mAHP). These findings demonstrate that heteromeric nicotinic excitation of ECVI neurons differs between male and female mice during a period of major circuitry development within the HF, which may have mechanistic implications for known sex differences in the development and function of this cognitive brain region.
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Affiliation(s)
- Beryl Y T Chung
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Craig D C Bailey
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
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Montgomery KS, Bancroft EA, Fincher AS, Migut EA, Provasek V, Murchison D, DuBois DW. Effects of ethanol and varenicline on female Sprague-Dawley rats in a third trimester model of fetal alcohol syndrome. Alcohol 2018; 71:75-87. [PMID: 30059955 DOI: 10.1016/j.alcohol.2018.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/03/2018] [Accepted: 02/26/2018] [Indexed: 12/17/2022]
Abstract
Perinatal ethanol exposure disrupts a variety of developmental processes in neurons important for establishing a healthy brain. These ethanol-induced impairments known as fetal alcohol spectrum disorder (FASD) are not fully understood, and currently, there is no effective treatment. Further, growing evidence suggests that adult females are more susceptible to ethanol, with the effects of perinatal ethanol exposure also being sexually divergent. Female models have been historically underutilized in neurophysiological investigations, but here, we used a third-trimester binge-ethanol model of FASD to examine changes to basal forebrain (BF) physiology and behavior in female Sprague-Dawley rats. We also tested varenicline as a potential cholinomimetic therapeutic. Rat pups were gavage-treated with binge-like ethanol, varenicline and ethanol, and varenicline alone. Using patch-clamp electrophysiology in BF slices, we observed that binge-ethanol exposure increased spontaneous post-synaptic current (sPSC) frequency. Varenicline exposure alone also enhanced sPSC frequency. Varenicline plus ethanol co-treatment prevented the sPSC frequency increase. Changes in BF synaptic transmission persisted into adolescence after binge-ethanol treatment. Behaviorally, binge-ethanol treated females displayed increased anxiety (thigmotaxis) and demonstrated learning deficits in the water maze. Varenicline/ethanol co-treatment was effective at reducing these behavioral deficits. In the open field, ethanol-treated rats displayed longer distances traveled and spent less time in the center of the open field box. Co-treated rats displayed less anxiety, demonstrating a possible effect of varenicline on this measure. In conclusion, ethanol-induced changes in both BF synaptic transmission and behavior were reduced by varenicline in female rats, supporting a role for cholinergic therapeutics in FASD treatment.
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Moshé SL. The 2017 Sachs Lecture: Kindling Knowledge in Epilepsy. Pediatr Neurol 2018; 85:5-12. [PMID: 29958806 DOI: 10.1016/j.pediatrneurol.2018.03.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 03/26/2018] [Indexed: 10/17/2022]
Affiliation(s)
- Solomon L Moshé
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, New York; Dominick P. Purpura Department of Neuroscience, Montefiore/Einstein Epilepsy Center, Albert Einstein College of Medicine, Bronx, New York; Department of Pediatrics, Albert Einstein College of Medicine, Bronx, New York.
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Roux S, Lohof A, Ben-Ari Y, Poulain B, Bossu JL. Maturation of GABAergic Transmission in Cerebellar Purkinje Cells Is Sex Dependent and Altered in the Valproate Model of Autism. Front Cell Neurosci 2018; 12:232. [PMID: 30104962 PMCID: PMC6077203 DOI: 10.3389/fncel.2018.00232] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/16/2018] [Indexed: 12/20/2022] Open
Abstract
Brain development is accompanied by a shift in gamma-aminobutyric acid (GABA) response from depolarizing-excitatory to hyperpolarizing-inhibitory, due to a reduction of intracellular chloride concentration. This sequence is delayed in Autism Spectrum Disorders (ASD). We now report a similar alteration of this shift in the cerebellum, a structure implicated in ASD. Using single GABAA receptor channel recordings in cerebellar Purkinje cells (PCs), we found two conductance levels (18 and 10 pS), the former being dominant in newborns and the latter in young-adults. This conductance shift and the depolarizing/excitatory to hyperpolarizing/inhibitory GABA shift occurred 4 days later in females than males. Our data support a sex-dependent developmental shift of GABA conductance and chloride gradient, leading to different developmental timing in males and females. Because these developmental sequences are altered in ASD, this study further stresses the importance of developmental timing in pathological neurodevelopment.
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Affiliation(s)
- Sébastien Roux
- Institut des Neurosciences Cellulaires et Intégratives (INCI)-CNRS, UPR 3212, Strasbourg, France
| | - Ann Lohof
- Sorbonne Université, CNRS UMR 8256, Biological Adaptation and Ageing, Paris, France
| | - Yehezkel Ben-Ari
- Neurochlore, Ben-Ari Institute of Neuroarcheology, Campus Scientifique de Luminy, Aix Marseille Université, Marseille, France
| | - Bernard Poulain
- Institut des Neurosciences Cellulaires et Intégratives (INCI)-CNRS, UPR 3212, Strasbourg, France
| | - Jean-Louis Bossu
- Institut des Neurosciences Cellulaires et Intégratives (INCI)-CNRS, UPR 3212, Strasbourg, France
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Abstract
Epilepsy is a chronic neurological disorder affecting 65 million people worldwide. The etiologies of seizures can often be identified as genetic, metabolic, structural, immunologic or infectious, but in many cases the cause is unknown with the current diagnostic tools. Epileptogenesis is a process during which genetic or other acquired etiologies/insults lead to functional, structural, or network reorganization changes in the brain that may lead to the development of, or progression of, spontaneous seizures. During development, there are continuous changes in the structure, function, and network operation that also show sex specificity, which may alter the mechanisms underlying the generation of seizures (ictogenesis) and epileptogenesis. Understanding the mechanisms of early life epileptogenesis will enable the development of rationally designed age- and sex-appropriate therapies that would improve the overall quality of patients' lives. Here, we discuss some of these processes that may affect seizure generation and epileptogenesis in the neonatal brain.
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Affiliation(s)
- Anna-Maria Katsarou
- Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA,Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Aristea S. Galanopoulou
- Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA,Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, New York, USA,Montefiore/Einstein Epilepsy Center, Albert Einstein College of Medicine, Bronx, New York, USA,Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Solomon L. Moshé
- Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA,Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, New York, USA,Montefiore/Einstein Epilepsy Center, Albert Einstein College of Medicine, Bronx, New York, USA,Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA,Department of Pediatrics, Albert Einstein College of Medicine, Bronx, New York, USA,Corresponding author. Address: Department of Neurology, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Rose F. Kennedy Center, Rm 316, Bronx, NY 10461, USA. Tel.: +1 718-430-2447; fax: +1 718-430-8899. (S.L. Moshé)
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Developmental excitatory-to-inhibitory GABA polarity switch is delayed in Ts65Dn mice, a genetic model of Down syndrome. Neurobiol Dis 2018; 115:1-8. [PMID: 29550538 DOI: 10.1016/j.nbd.2018.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/01/2018] [Accepted: 03/07/2018] [Indexed: 11/23/2022] Open
Abstract
Down syndrome (DS) is the most frequent genetic cause of developmental abnormalities leading to intellectual disability. One notable phenomenon affecting the formation of nascent neural circuits during late developmental periods is developmental switch of GABA action from depolarizing to hyperpolarizing mode. We examined properties of this switch in DS using primary cultures and acute hippocampal slices from Ts65Dn mice, a genetic model of DS. Cultures of DIV3-DIV13 Ts65Dn and control normosomic (2 N) neurons were loaded with FURA-2 AM, and GABA action was assessed using local applications. In 2 N cultures, the number of GABA-activated cells dropped from ~100% to 20% between postnatal days 3-13 (P3-P13) reflecting the switch in GABA action polarity. In Ts65Dn cultures, the timing of this switch was delayed by 2-3 days. Next, microelectrode recordings of multi-unit activity (MUA) were performed in CA3 slices during bath application of the GABAA agonist isoguvacine. MUA frequency was increased in P8-P12 and reduced in P14-P22 slices reflecting the switch of GABA action from excitatory to inhibitory mode. The timing of this switch was delayed in Ts65Dn by approximately 2 days. Finally, frequency of giant depolarizing potentials (GDPs), a form of primordial neural activity, was significantly increased in slices from Ts65Dn pups at P12 and P14. These experimental evidences show that GABA action polarity switch is delayed in Ts65Dn model of DS, and that these changes lead to a delay in maturation of nascent neural circuits. These alterations may affect properties of neural circuits in adult animals and, therefore, represent a prospective target for pharmacotherapy of cognitive impairment in DS.
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Katsarou A, Moshé SL, Galanopoulou AS. INTERNEURONOPATHIES AND THEIR ROLE IN EARLY LIFE EPILEPSIES AND NEURODEVELOPMENTAL DISORDERS. Epilepsia Open 2017; 2:284-306. [PMID: 29062978 PMCID: PMC5650248 DOI: 10.1002/epi4.12062] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2017] [Indexed: 12/22/2022] Open
Abstract
GABAergic interneurons control the neural circuitry and network activity in the brain. The advances in genetics have identified genes that control the development, maturation and integration of GABAergic interneurons and implicated them in the pathogenesis of epileptic encephalopathies or neurodevelopmental disorders. For example, mutations of the Aristaless-Related homeobox X-linked gene (ARX) may result in defective GABAergic interneuronal migration in infants with epileptic encephalopathies like West syndrome (WS), Ohtahara syndrome or X-linked lissencephaly with abnormal genitalia (XLAG). The concept of "interneuronopathy", i.e. impaired development, migration or function of interneurons, has emerged as a possible etiopathogenic mechanism for epileptic encephalopathies. Treatments that enhance GABA levels, may help seizure control but do not necessarily show disease modifying effect. On the other hand, interneuronopathies can be seen in other conditions in which epilepsy may not be the primary manifestation, such as autism. In this review, we plan to outline briefly the current state of knowledge on the origin, development, and migration and integration of GABAergic interneurons, present neurodevelopmental conditions, with or without epilepsy, that have been associated with interneuronopathies and discuss the evidence linking certain types of interneuronal dysfunction with epilepsy and/or cognitive or behavioral deficits.
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Affiliation(s)
- Anna‐Maria Katsarou
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Solomon L. Moshé
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Department of PediatricsAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Aristea S. Galanopoulou
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
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Sampath D, Valdez R, White AM, Raol YH. Anticonvulsant effect of flupirtine in an animal model of neonatal hypoxic-ischemic encephalopathy. Neuropharmacology 2017; 123:126-135. [PMID: 28587899 DOI: 10.1016/j.neuropharm.2017.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 05/07/2017] [Accepted: 06/02/2017] [Indexed: 12/20/2022]
Abstract
Research studies suggest that neonatal seizures, which are most commonly associated with hypoxic-ischemic injury, may contribute to brain injury and adverse neurologic outcome. Unfortunately, neonatal seizures are often resistant to treatment with current anticonvulsants. In the present study, we evaluated the efficacy of flupirtine, administered at clinically relevant time-points, for the treatment of neonatal seizures in an animal model of hypoxic-ischemic injury that closely replicates features of the human syndrome. We also compared the efficacy of flupirtine to that of phenobarbital, the current first-line drug for neonatal seizures. Flupirtine is a KCNQ potassium channel opener. KCNQ channels play an important role in controlling brain excitability during early development. In this study, hypoxic-ischemic injury was induced in neonatal rats, and synchronized video-EEG records were acquired at various time-points during the experiment to identify seizures. The results revealed that flupirtine, administered either 5 min after the first electroclinical seizure, or following completion of 2 h of hypoxia, i.e., during the immediate reperfusion period, reduced the number of rats with electroclinical seizures, and also the frequency and total duration of electroclinical seizures. Further, daily dosing of flupirtine decreased the seizure burden over 3 days following HI-induction, and modified the natural evolution of acute seizures. Moreover, compared to a therapeutic dose of phenobarbital, which was modestly effective against electroclinical seizures, flupirtine showed greater efficacy. Our results indicate that flupirtine is an extremely effective treatment for neonatal seizures in rats and provide evidence for a trial of this medication in newborn humans.
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Affiliation(s)
- Dayalan Sampath
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Robert Valdez
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Andrew M White
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Yogendra H Raol
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA.
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Developmental pharmacology of benzodiazepines under normal and pathological conditions. Epileptic Disord 2016; 16 Spec No 1:S59-68. [PMID: 25335485 DOI: 10.1684/epd.2014.0690] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Benzodiazepines are allosteric agonists of GABAA receptors (GABAAR), pentameric ligand-gated Cl(-) channels, which serve both an important neurodevelopmental role but are also the principal inhibitory system in the brain. However, their subunit composition, channel properties, and function, as well as their region-specific expression patterns, change through development. These processes have been extensively studied in rodents and to some extent confirmed in higher species. Specifically, GABAARs acquire faster kinetics with age and their pharmacology changes rendering them more sensitive to drugs that have higher affinity for α1 subunit-containing GABAARs, such as benzodiazepines, but also, their inhibitory function becomes more potent as they shift from having depolarising to hyperpolarising responses due to a shift in Cl(-) gradient and cation chloride cotransporter expression. Concerns have been raised about possible pro-apoptotic and paradoxical effects of benzodiazepines in the neonatal normal rat brain, although it is unclear, as yet, whether this extends to brains exposed to seizures. Growing evidence indicates that the pharmacology and physiology of GABAARs may be altered in the brain of rats or humans with seizures or epilepsy, or different aetiologies that predispose to epilepsy. These changes follow different paths, depending on sex, age, region, cell type, aetiology, or time-point specific factors. Identification of dynamic biomarkers that could enable these changes in vivo to be monitored would greatly facilitate the selection of more effective agonists with fewer side effects.
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Age- and sex-related characteristics of tonic GABA currents in the rat substantia nigra pars reticulata. Neurochem Res 2015; 40:747-57. [PMID: 25645446 DOI: 10.1007/s11064-015-1523-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/09/2015] [Accepted: 01/13/2015] [Indexed: 12/19/2022]
Abstract
Previous studies have shown that the pharmacologic effects of GABAergic drugs and the postsynaptic phasic GABAAergic inhibitory responses in the anterior part of the rat substantia nigra pars reticulata (SNRA) are age- and sex-specific. Here, we investigate whether there are age- and sex-related differences in the expression of the δ GABAA receptor (GABAAR) subunit and GABAAR mediated tonic currents. We have used δ-specific immunochemistry and whole cell patch clamp to study GABAAR mediated tonic currents in the SNRA of male and female postnatal day (PN) PN5-9, PN11-16, and PN25-32 rats. We observed age-related decline, but no sex-specific changes, in bicuculline (BIM) sensitive GABAAR tonic current density, which correlated with the decline in δ subunit in the SNRA between PN15 and 30. Furthermore, we show that the GABAAR tonic currents can be modified by muscimol (GABAAR agonist; partial GABACR agonist), THIP (4,5,6,7-tetrahydroisoxazolo (5,4-c)pyridin-3-ol: α4β3δ GABAARs agonist and GABACR antagonist), and zolpidem (α1-subunit selective GABAAR agonist) in age- and sex-dependent manner specific for each drug. We propose that the emergence of the GABAAR-sensitive anticonvulsant effects of the rat SNRA during development may depend upon the developmental decline in tonic GABAergic inhibition of the activity of rat SNRA neurons, although other sex-specific factors are also involved.
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Kight KE, McCarthy MM. Using sex differences in the developing brain to identify nodes of influence for seizure susceptibility and epileptogenesis. Neurobiol Dis 2014; 72 Pt B:136-43. [PMID: 24892888 PMCID: PMC5322568 DOI: 10.1016/j.nbd.2014.05.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/12/2014] [Accepted: 05/22/2014] [Indexed: 12/12/2022] Open
Abstract
Sexual differentiation of the developing brain organizes the neural architecture differently between males and females, and the main influence on this process is exposure to gonadal steroids during sensitive periods of prenatal and early postnatal development. Many molecular and cellular processes are influenced by steroid hormones in the developing brain, including gene expression, cell birth and death, neurite outgrowth and synaptogenesis, and synaptic activity. Perturbations in these processes can alter neuronal excitability and circuit activity, leading to increased seizure susceptibility and the promotion of pathological processes that constitute epileptogenesis. In this review, we will provide a general overview of sex differences in the early developing brain that may be relevant for altered seizure susceptibility in early life, focusing on limbic areas of the brain. Sex differences that have the potential to alter the progress of epileptogenesis are evident at molecular and cellular levels in the developing brain, and include differences in neuronal excitability, response to environmental insult, and epigenetic control of gene expression. Knowing how these processes differ between the sexes can help us understand fundamental mechanisms underlying gender differences in seizure susceptibility and epileptogenesis.
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Affiliation(s)
- Katherine E Kight
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Margaret M McCarthy
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Pharmacology and Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Akman O, Moshé SL, Galanopoulou AS. Early life status epilepticus and stress have distinct and sex-specific effects on learning, subsequent seizure outcomes, including anticonvulsant response to phenobarbital. CNS Neurosci Ther 2014; 21:181-92. [PMID: 25311088 DOI: 10.1111/cns.12335] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 09/14/2014] [Accepted: 09/15/2014] [Indexed: 12/25/2022] Open
Abstract
AIMS Neonatal status epilepticus (SE) is often associated with adverse cognitive and epilepsy outcomes. We investigate the effects of three episodes of kainic acid-induced SE (3KA-SE) and maternal separation in immature rats on subsequent learning, seizure susceptibility, and consequences, and the anticonvulsant effects of phenobarbital, according to sex, type, and age at early life (EL) event. METHODS 3KA-SE or maternal separation was induced on postnatal days (PN) 4-6 or 14-16. Rats were tested on Barnes maze (PN16-19), or lithium-pilocarpine SE (PN19) or flurothyl seizures (PN32). The anticonvulsant effects of phenobarbital (20 or 40 mg/kg/rat, intraperitoneally) pretreatment were tested on flurothyl seizures. FluoroJadeB staining assessed hippocampal injury. RESULTS 3KA-SE or separation on PN4-6 caused more transient learning delays in males and did not alter lithium-pilocarpine SE latencies, but aggravated its outcomes in females. Anticonvulsant effects of phenobarbital were preserved and potentiated in specific groups depending on sex, type, and age at EL event. CONCLUSIONS Early life 3KA-SE and maternal separation cause more but transient cognitive deficits in males but aggravate the consequences of subsequent lithium-pilocarpine SE in females. In contrast, on flurothyl seizures, EL events showed either beneficial or no effect, depending on gender, type, and age at EL events.
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Affiliation(s)
- Ozlem Akman
- Saul R. Korey Department of Neurology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA; Department of Physiology, Faculty of Medicine, Istanbul Bilim University, Istanbul, Turkey
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23
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Bolton MM, Heaney CF, Murtishaw AS, Sabbagh JJ, Magcalas CM, Kinney JW. Postnatal alterations in GABA
B
receptor tone produce sensorimotor gating deficits and protein level differences in adulthood. Int J Dev Neurosci 2014; 41:17-27. [DOI: 10.1016/j.ijdevneu.2014.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/30/2014] [Accepted: 10/01/2014] [Indexed: 01/05/2023] Open
Affiliation(s)
- Monica M. Bolton
- Behavioral Neuroscience LaboratoryDepartment of PsychologyUniversity of NevadaLas VegasUnited States
| | - Chelcie F. Heaney
- Behavioral Neuroscience LaboratoryDepartment of PsychologyUniversity of NevadaLas VegasUnited States
| | - Andrew S. Murtishaw
- Behavioral Neuroscience LaboratoryDepartment of PsychologyUniversity of NevadaLas VegasUnited States
| | - Jonathan J. Sabbagh
- Behavioral Neuroscience LaboratoryDepartment of PsychologyUniversity of NevadaLas VegasUnited States
| | - Christy M. Magcalas
- Behavioral Neuroscience LaboratoryDepartment of PsychologyUniversity of NevadaLas VegasUnited States
| | - Jefferson W. Kinney
- Behavioral Neuroscience LaboratoryDepartment of PsychologyUniversity of NevadaLas VegasUnited States
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Akman O, Moshé SL, Galanopoulou AS. Sex-specific consequences of early life seizures. Neurobiol Dis 2014; 72 Pt B:153-66. [PMID: 24874547 DOI: 10.1016/j.nbd.2014.05.021] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 05/07/2014] [Accepted: 05/17/2014] [Indexed: 12/29/2022] Open
Abstract
Seizures are very common in the early periods of life and are often associated with poor neurologic outcome in humans. Animal studies have provided evidence that early life seizures may disrupt neuronal differentiation and connectivity, signaling pathways, and the function of various neuronal networks. There is growing experimental evidence that many signaling pathways, like GABAA receptor signaling, the cellular physiology and differentiation, or the functional maturation of certain brain regions, including those involved in seizure control, mature differently in males and females. However, most experimental studies of early life seizures have not directly investigated the importance of sex on the consequences of early life seizures. The sexual dimorphism of the developing brain raises the question that early seizures could have distinct effects in immature females and males that are subjected to seizures. We will first discuss the evidence for sex-specific features of the developing brain that could be involved in modifying the susceptibility and consequences of early life seizures. We will then review how sex-related biological factors could modify the age-specific consequences of induced seizures in the immature animals. These include signaling pathways (e.g., GABAA receptors), steroid hormones, growth factors. Overall, there are very few studies that have specifically addressed seizure outcomes in developing animals as a function of sex. The available literature indicates that a variety of outcomes (histopathological, behavioral, molecular, epileptogenesis) may be affected in a sex-, age-, region-specific manner after seizures during development. Obtaining a better understanding for the gender-related mechanisms underlying epileptogenesis and seizure comorbidities will be necessary to develop better gender and age appropriate therapies.
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Affiliation(s)
- Ozlem Akman
- Department of Physiology, Faculty of Medicine, Istanbul Bilim University, 34394 Istanbul, Turkey.
| | - Solomon L Moshé
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Montefiore Epilepsy Management Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, 10461, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, 10461, USA; Department of Pediatrics, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, 10461, USA
| | - Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Montefiore Epilepsy Management Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, 10461, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, 10461, USA
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Giorgi FS, Galanopoulou AS, Moshé SL. Sex dimorphism in seizure-controlling networks. Neurobiol Dis 2014; 72 Pt B:144-52. [PMID: 24851800 DOI: 10.1016/j.nbd.2014.05.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/02/2014] [Accepted: 05/06/2014] [Indexed: 11/27/2022] Open
Abstract
Males and females show a different predisposition to certain types of seizures in clinical studies. Animal studies have provided growing evidence for sexual dimorphism of certain brain regions, including those that control seizures. Seizures are modulated by networks involving subcortical structures, including thalamus, reticular formation nuclei, and structures belonging to the basal ganglia. In animal models, the substantia nigra pars reticulata (SNR) is the best studied of these areas, given its relevant role in the expression and control of seizures throughout development in the rat. Studies with bilateral infusions of the GABA(A) receptor agonist muscimol have identified distinct roles of the anterior or posterior rat SNR in flurothyl seizure control, that follow sex-specific maturational patterns during development. These studies indicate that (a) the regional functional compartmentalization of the SNR appears only after the third week of life, (b) only the male SNR exhibits muscimol-sensitive proconvulsant effects which, in older animals, is confined to the posterior SNR, and (c) the expression of the muscimol-sensitive anticonvulsant effects become apparent earlier in females than in males. The first three postnatal days are crucial in determining the expression of the muscimol-sensitive proconvulsant effects of the immature male SNR, depending on the gonadal hormone setting. Activation of the androgen receptors during this early period seems to be important for the formation of this proconvulsant SNR region. We describe molecular/anatomical candidates underlying these age- and sex-related differences, as derived from in vitro and in vivo experiments, as well as by [(14)C]2-deoxyglucose autoradiography. These involve sex-specific patterns in the developmental changes in the structure or physiology or GABA(A) receptors or of other subcortical structures (e.g., locus coeruleus, hippocampus) that may affect the function of seizure-controlling networks.
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Affiliation(s)
- Fillippo Sean Giorgi
- Department of Clinical and Experimental Medicine, Section of Neurology, University of Pisa-Pisa University Hospital, I56126 Pisa, Italy.
| | - Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Montefiore Epilepsy Management Center, and Dominick P. Purpura Department of Neuroscience, Bronx, NY, 10461, USA
| | - Solomon L Moshé
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Montefiore Epilepsy Management Center, and Dominick P. Purpura Department of Neuroscience, Bronx, NY, 10461, USA; Department of Pediatrics, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, 10461, USA
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Tuchman R, Hirtz D, Mamounas LA. NINDS epilepsy and autism spectrum disorders workshop report. Neurology 2013; 81:1630-6. [PMID: 24089385 DOI: 10.1212/wnl.0b013e3182a9f482] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The association of epilepsy and autism spectrum disorders (ASD), although well-recognized, is poorly understood. The purpose of this report is to summarize the discussion of a workshop sponsored by the National Institute of Neurological Disorders and Stroke, with support from the National Institute of Child Health and Human Development, Autism Speaks, and Citizens United for Research in Epilepsy, that took place in Bethesda, Maryland, on May 29 and 30, 2012. The goals of this workshop were to highlight the clinical and biological relationships between ASD and epilepsy, to determine both short- and long-term goals that address research and treatment conundrums in individuals with both ASD and epilepsy, and to identify resources that can further both clinical and basic research. Topics discussed included epidemiology, genetics, environmental factors, common mechanisms, neuroimaging, neuropathology, neurophysiology, treatment, and research gaps and challenges in this unique population.
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Affiliation(s)
- Roberto Tuchman
- From the Department of Neurology (R.T.), Miami Children's Hospital Dan Marino Center, Weston, FL; and National Institute of Neurological Disorders and Stroke (D.H., L.A.M.), National Institutes of Health, Bethesda, MD
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Esterlis I, McKee SA, Kirk K, Lee D, Bois F, Stiklus SM, Seibyl JP, Krishnan-Sarin S, O'Malley SS, Staley JK, Cosgrove KP. Sex-specific differences in GABA(A) -benzodiazepine receptor availability: relationship with sensitivity to pain and tobacco smoking craving. Addict Biol 2013; 18:370-8. [PMID: 22353491 DOI: 10.1111/j.1369-1600.2011.00403.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Sex differences exist in tobacco smoking behaviors. Nicotine, the primary addictive ingredient in tobacco smoke, indirectly affects γ-amino butyric acid (GABA) function. Previous studies reported sex-by-smoking interactions in brain GABA levels. The goal of the present study was to evaluate if there is a sex-by-smoking interaction at the GABA(A)-benzodiazepine receptors (GABA(A)-BZRs), as well as relationships between GABA(A)-BZR availability and behavioral variables before and after 1 week of smoking cessation. Twenty-six women (8 non-smokers, age 36.0 ± 13.4 years; 19 smokers, age 34.6 ± 8.9 years) and 25 men (8 non-smokers, age 37.9 ± 13.8 years; 17 smokers, 34.1 ± 12.4 years) were imaged using [123I]iomazenil and single-photon emission computed tomography. Smokers were imaged at baseline 7 hours after the last cigarette. A significantly great number of men were able to abstain from smoking for 1 week (P = 0.003). There were no significant differences in nicotine dependence and cigarette craving, mood or pain sensitivity between male and female smokers. There was a significant effect of gender across all brain regions (frontal, parietal, anterior cingulate, temporal and occipital cortices, and cerebellum; P < 0.05), with all women (smokers and non-smokers combined) having a higher GABA(A)-BZR availability than all men. There was a negative correlation between GABA(A)-BZR availability and craving (P ≤ 0.02) and pain sensitivity (P = 0.04) in female smokers but not male smokers. This study provides further evidence of a sex-specific regulation of GABA(A)-BZR availability in humans and demonstrates the potential for GABA(A)-BZRs to mediate tobacco smoking craving and pain symptoms differentially in female and male smokers.
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Affiliation(s)
- Irina Esterlis
- Department of Psychiatry, Yale University and the VACHS, West Haven, CT 06516, USA.
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Robbins MA, Ryan CL, Marriott AL, Doucette TA. Temporal Memory Dysfunction and Alterations in Tyrosine Hydroxylase Immunoreactivity in Adult Rats Following Neonatal Exposure to Domoic Acid. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/nm.2013.41005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Sumich AL, Sarkar S, Hermens DF, Ibrahimovic A, Kelesidi K, Wilson D, Rubia K. Sex differences in brain maturation as measured using event-related potentials. Dev Neuropsychol 2012; 37:415-33. [PMID: 22799761 DOI: 10.1080/87565641.2011.653461] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Little is known about how sex influences functional brain maturation. The current study investigated sex differences in the maturation of event-related potential (ERP) amplitudes during an auditory oddball task (N = 170; age = 6-17 years). Performance improved with age. N200 amplitude declined with age: parietal sites showed earlier development than temporal and frontal locations. Girls showed greater bilateral frontal P300 amplitude development, approaching the higher values observed in boys during childhood. After controlling for age, right frontal P300 amplitude was associated with reaction time in girls. The findings demonstrate sex differences in ERP maturation in line with behavioral and neuroimaging studies.
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Affiliation(s)
- Alexander L Sumich
- Division of Psychology, School of Social Sciences, Nottingham Trent University, Nottingham, United Kingdom.
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30
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Kozlov AP, Nizhnikov ME, Varlinskaya EI, Spear NE. The role of social isolation in ethanol effects on the preweanling rat. Behav Brain Res 2012; 227:43-57. [PMID: 22051944 DOI: 10.1016/j.bbr.2011.10.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 10/19/2011] [Indexed: 01/08/2023]
Abstract
The present experiments investigated the effects of acute ethanol exposure on voluntary intake of 0.1% saccharin or water as well as behavioral and nociceptive reactivity in 12-day-old (P12) rats exposed to differing levels of isolation. The effects of ethanol emerged only during short-term social isolation (STSI) with different patterns observed in males and females and in pups exposed to saccharin or water. The 0.5g/kg ethanol dose selectively increased saccharin intake in females, decreased rearing activity in males and attenuated isolation-induced analgesia (IIA) in all water-exposed pups. Ingestion of saccharin decreased IIA, and the 0.5g/kg ethanol dose further reduced IIA. The 1.0g/kg ethanol dose, administered either intragastrically or intraparentionally, also decreased IIA in P12 females, but not in P9 pups. A significant correlation between voluntary saccharin intake and baseline nociceptive reactivity was revealed in saline injected animals, saccharin intake was inversely correlated with behavioral activation and latency of reaction to noxious heat after 0.5g/kg ethanol in females. The 0.5g/kg ethanol dose did not affect plasma corticosterone (CORT) measured 5h after maternal separation or 20min after ethanol injection. Female pups CORT level was inversely correlated with magnitude of IIA that accompanied the first episode of STSI (pretest isolation) 1.5-2h before CORT measurement. The present findings suggest that the anxiolytic properties of ethanol are responsible for enhancement of saccharin intake during STSI. Furthermore, differential reactivity of P12 males and females to STSI plays an important role in ethanol effects observed at this age.
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Affiliation(s)
- Andrey P Kozlov
- Center for Development & Behavioral Neuroscience, Department of Psychology, Binghamton University, Binghamton, NY 13902-6000, United States
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31
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Waddell J, McCarthy MM. Sexual differentiation of the brain and ADHD: what is a sex difference in prevalence telling us? Curr Top Behav Neurosci 2012; 9:341-60. [PMID: 21120649 PMCID: PMC4841632 DOI: 10.1007/7854_2010_114] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Sexual differentiation of the brain is a function of various processes that prepare the organism for successful reproduction in adulthood. Release of gonadal steroids during both the perinatal and the pubertal stages of development organizes many sex differences, producing changes in brain excitability and morphology that endure across the lifespan. To achieve these sexual dimorphisms, gonadal steroids capitalize on a number of distinct mechanisms across brain regions. Comparison of the developing male and female brain provides insight into the mechanisms through which synaptic connections are made, and circuits are organized that mediate sexually dimorphic behaviors. The prevalence of most psychiatric and neurological disorders differ in males versus females, including disorders of attention, activity and impulse control. While there is a strong male bias in incidence of attention deficit and hyperactivity disorders, the source of that bias remains controversial. By elucidating the biological underpinnings of male versus female brain development, we gain a greater understanding of how hormones and genes do and do not contribute to the differential vulnerability in one sex versus the other.
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Affiliation(s)
- Jaylyn Waddell
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA,
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32
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Altered GABA signaling in early life epilepsies. Neural Plast 2011; 2011:527605. [PMID: 21826277 PMCID: PMC3150203 DOI: 10.1155/2011/527605] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 05/04/2011] [Accepted: 05/27/2011] [Indexed: 01/13/2023] Open
Abstract
The incidence of seizures is particularly high in the early ages of life. The immaturity of inhibitory systems, such as GABA, during normal brain development and its further dysregulation under pathological conditions that predispose to seizures have been speculated to play a major role in facilitating seizures. Seizures can further impair or disrupt GABAA signaling by reshuffling the subunit composition of its receptors or causing aberrant reappearance of depolarizing or hyperpolarizing GABAA receptor currents. Such effects may not result in epileptogenesis as frequently as they do in adults. Given the central role of GABAA signaling in brain function and development, perturbation of its physiological role may interfere with neuronal morphology, differentiation, and connectivity, manifesting as cognitive or neurodevelopmental deficits. The current GABAergic antiepileptic drugs, while often effective for adults, are not always capable of stopping seizures and preventing their sequelae in neonates. Recent studies have explored the therapeutic potential of chloride cotransporter inhibitors, such as bumetanide, as adjunctive therapies of neonatal seizures. However, more needs to be known so as to develop therapies capable of stopping seizures while preserving the age- and sex-appropriate development of the brain.
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Ryan CL, Robbins MA, Smith MT, Gallant IC, Adams-Marriott AL, Doucette TA. Altered social interaction in adult rats following neonatal treatment with domoic acid. Physiol Behav 2011; 102:291-5. [DOI: 10.1016/j.physbeh.2010.11.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 11/02/2010] [Accepted: 11/15/2010] [Indexed: 12/31/2022]
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Velísková J, Moshé SL. Update on the role of substantia nigra pars reticulata in the regulation of seizures. Epilepsy Curr 2010; 6:83-7. [PMID: 16761069 PMCID: PMC1464157 DOI: 10.1111/j.1535-7511.2006.00106.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The substantia nigra pars reticulata (SNR) represents an endogenous seizure suppressing system, which may be targeted to develop treatments for generalized or multifocal epilepsies. This review summarizes the region-, age-, and sex-specific features of the SNR-based seizure-controlling network.
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Affiliation(s)
- Jana Velísková
- Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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35
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Gill DA, Ramsay SL, Tasker RA. Selective reductions in subpopulations of GABAergic neurons in a developmental rat model of epilepsy. Brain Res 2010; 1331:114-23. [PMID: 20331981 DOI: 10.1016/j.brainres.2010.03.054] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Revised: 03/15/2010] [Accepted: 03/15/2010] [Indexed: 01/17/2023]
Abstract
In the rat, early postnatal development is a critical period for neuronal migration, differentiation and network formation, requiring appropriate and timely glutamate and gamma-aminobutyric acid (GABA) signaling. Insults that affect either of these systems may result in increased excitatory activity, potentially leading to changes in neuronal proliferation and/or connectivity. We have previously shown that postnatal administration of low doses of domoic acid (DOM) can produce many of the behavioral and morphological changes found in current animal models of temporal lobe epilepsy (TLE), as well as the human condition. Using immunohistochemical techniques, we sought to characterize alterations in specific hippocampal GABAergic subpopulations at various locations along the septo-temporal axis in the DOM model. Results show decreased levels of the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD) in the ventral hilus and region- and sex-specific reductions in parvalbumin (PV)-containing immunoreactivity, but no alterations in somatostatin (SST) expression. These regional and sex-dependent changes in specific subpopulations of GABAergic interneurons may contribute to seizure development in this slowly progressing developmental model of TLE, and highlight how even subtle intervention may alter the interplay between glutamate and GABA systems during critical developmental stages.
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Affiliation(s)
- Daphne A Gill
- Department of Biomedical Sciences, University of Prince Edward Island, Charlottetown, PE, Canada
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Kozlov AP, Nizhnikov ME, Varlinskaya EI, Spear NE. Pharmacological effects of ethanol on ingestive behavior of the preweanling rat. Behav Brain Res 2009; 205:162-74. [PMID: 19549546 PMCID: PMC2753683 DOI: 10.1016/j.bbr.2009.06.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 06/09/2009] [Accepted: 06/15/2009] [Indexed: 01/03/2023]
Abstract
The present study was designed to test the hypothesis that sensitivity of ingestive behavior of infant rat to the pharmacological effects of ethanol changes between postnatal (P) days 9 and 12. The intake of 0.1% saccharin and water, general motor activity, and myoclonic twitching activity were assessed following administration of three doses of ethanol (0, 0.25, and 0.5 g/kg) while fluids were free available to the animals. The 0.5 g/kg dose of ethanol attenuated saccharin intake in P9 pups and enhanced saccharin intake in P12 rats. On P12 some sex-related differences emerged at 0.5 g/kg of ethanol, with saccharin intake being higher in females than in their male counterparts. Taste reactivity probe revealed that 0.5 g/kg of ethanol increased taste responsiveness to saccharin on P12 but only to infusions presented at a high rate. The results of the present study indicate that ontogenetic changes in sensitivity to the effects of ethanol on ingestive behavior occur during the second postnatal week, with P9 animals being more sensitive to the inhibitory (sedative) effects on saccharin intake and P12 rats being more sensitive to the stimulatory effects of ethanol. We suggest that acute ethanol enhanced saccharin intake via sensitization of oral response to appetitive taste stimulation.
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Affiliation(s)
- Andrey P Kozlov
- Center for Development & Behavioral Neuroscience, Department of Psychology, Binghamton University, Binghamton, NY 13902-6000, United States
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37
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Galanopoulou AS. Sexually dimorphic expression of KCC2 and GABA function. Epilepsy Res 2008; 80:99-113. [PMID: 18524541 PMCID: PMC2613346 DOI: 10.1016/j.eplepsyres.2008.04.013] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Revised: 04/06/2008] [Accepted: 04/07/2008] [Indexed: 12/13/2022]
Abstract
GABA(A) receptors have an age-adapted function in the brain. During early development, they mediate depolarizing effects, which result in activation of calcium-sensitive signaling processes that are important for the differentiation of the brain. In more mature stages of development and in adults, GABA(A) receptors acquire their classical hyperpolarizing signaling. The switch from depolarizing to hyperpolarizing GABA(A)-ergic signaling is triggered through the developmental shift in the balance of chloride cotransporters that either increase (i.e. NKCC1) or decrease (i.e. KCC2) intracellular chloride. The maturation of GABA(A) signaling follows sex-specific patterns, which correlate with the developmental expression profiles of chloride cotransporters. This has first been demonstrated in the substantia nigra, where the switch occurs earlier in females than in males. As a result, there are sensitive periods during development when drugs or conditions that activate GABA(A) receptors mediate different transcriptional effects in males and females. Furthermore, neurons with depolarizing or hyperpolarizing GABA(A)-ergic signaling respond differently to neurotrophic factors like estrogens. Consequently, during sensitive developmental periods, GABA(A) receptors may act as broadcasters of sexually differentiating signals, promoting gender-appropriate brain development. This has particular implications in epilepsy, where both the pathophysiology and treatment of epileptic seizures involve GABA(A) receptor activation. It is important therefore to study separately the effects of these factors not only on the course of epilepsy but also design new treatments that may not necessarily disturb the gender-appropriate brain development.
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Affiliation(s)
- Aristea S Galanopoulou
- Albert Einstein College of Medicine, Saul R Korey Department of Neurology, Bronx, NY, USA.
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38
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Blockade of androgen receptors is sufficient to alter the sexual differentiation of the substantia nigra pars reticulata seizure-controlling network. Epileptic Disord 2008; 10:8-12. [PMID: 18367425 DOI: 10.1684/epd.2008.0160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Accepted: 12/16/2007] [Indexed: 11/17/2022]
Abstract
The substantia nigra pars reticulata (SNR) controls seizures in a sex-specific manner. At postnatal day 15 (P15), SNR infusion of GABA(A) receptor agonist muscimol have proconvulsant effects in males but not in females. In males, administration of an androgen receptor antagonist flutamide between P0-P2 led to the disappearance of the proconvulsant muscimol effects at P15. Thus, activation of androgen receptors is important for the presence of proconvulsant SNR muscimol responses.
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Foradori CD, Handa RJ. Living or dying in three quarter time: neonatal orchestration of hippocampal cell death pathways by androgens and excitatory GABA. Exp Neurol 2008; 213:1-6. [PMID: 18617165 DOI: 10.1016/j.expneurol.2008.04.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 04/25/2008] [Accepted: 04/30/2008] [Indexed: 11/18/2022]
Affiliation(s)
- C D Foradori
- Department of Biomedical Sciences, Neurobiology Section, Colorado State University, Fort Collins, CO 80523, USA
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40
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Galanopoulou AS. GABA(A) receptors in normal development and seizures: friends or foes? Curr Neuropharmacol 2008; 6:1-20. [PMID: 19305785 PMCID: PMC2645547 DOI: 10.2174/157015908783769653] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 05/24/2007] [Accepted: 08/05/2007] [Indexed: 12/26/2022] Open
Abstract
GABA(A) receptors have an age-adapted function in the brain. During early development, they mediate excitatory effects resulting in activation of calcium sensitive signaling processes that are important for the differentiation of the brain. In more mature stages of development and in adults, GABA(A) receptors transmit inhibitory signals. The maturation of GABA(A) signaling follows sex-specific patterns, which appear to also be important for the sexual differentiation of the brain. The inhibitory effects of GABA(A) receptor activation have been widely exploited in the treatment of conditions where neuronal silencing is necessary. For instance, drugs that target GABA(A) receptors are the mainstay of treatment of seizures. Recent evidence suggests however that the physiology and function of GABA(A) receptors changes in the brain of a subject that has epilepsy or status epilepticus.This review will summarize the physiology of and the developmental factors regulating the signaling and function of GABA(A) receptors; how these may change in the brain that has experienced prior seizures; what are the implications for the age and sex specific treatment of seizures and status epilepticus. Finally, the implications of these changes for the treatment of certain forms of medically refractory epilepsies and status epilepticus will be discussed.
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Affiliation(s)
- Aristea S Galanopoulou
- Albert Einstein College of Medicine, Saul R Korey Department of Neurology & Dominick P Purpura, Department of Neuroscience, Bronx NY, USA.
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Dissociated gender-specific effects of recurrent seizures on GABA signaling in CA1 pyramidal neurons: role of GABA(A) receptors. J Neurosci 2008; 28:1557-67. [PMID: 18272677 DOI: 10.1523/jneurosci.5180-07.2008] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Early in development, the depolarizing GABA(A)ergic signaling is needed for normal neuronal differentiation. It is shown here that hyperpolarizing reversal potentials of GABA(A)ergic postsynaptic currents (E(GABA)) appear earlier in female than in male rat CA1 pyramidal neurons because of increased potassium chloride cotransporter 2 (KCC2) expression and decreased bumetanide-sensitive chloride transport in females. Three episodes of neonatal kainic acid-induced status epilepticus (3KA-SE), each elicited at postnatal days 4 (P4)-P6, reverse the direction of GABA(A)ergic responses in both sexes. In males, 3KA-SE trigger a premature appearance of hyperpolarizing GABA(A)ergic signaling at P9, instead of P14. This is driven by an increase in KCC2 expression and decrease in bumetanide-sensitive chloride cotransport. In 3KA-SE females, E(GABA) transiently becomes depolarizing at P8-P13 because of increase in the activity of a bumetanide-sensitive NKCC1 (sodium potassium chloride cotransporter 1)-like chloride cotransporter. However, females regain their hyperpolarizing GABA(A)ergic signaling at P14 and do not manifest spontaneous seizures in adulthood. In maternally separated stressed controls, a hyperpolarizing shift in E(GABA) was observed in both sexes, associated with decreased bumetanide-sensitive chloride cotransport, whereas KCC2 immunoreactivity was increased in males only. GABA(A) receptor blockade at the time of 3KA-SE or maternal separation reversed their effects on E(GABA). These data suggest that the direction of GABA(A)-receptor signaling may be a determining factor for the age and sex-specific effects of prolonged seizures in the hippocampus, because they relate to normal brain development and possibly epileptogenesis. These effects differ from the consequences of severe stress.
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Ben-Ari Y, Gaiarsa JL, Tyzio R, Khazipov R. GABA: a pioneer transmitter that excites immature neurons and generates primitive oscillations. Physiol Rev 2007; 87:1215-84. [PMID: 17928584 DOI: 10.1152/physrev.00017.2006] [Citation(s) in RCA: 892] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Developing networks follow common rules to shift from silent cells to coactive networks that operate via thousands of synapses. This review deals with some of these rules and in particular those concerning the crucial role of the neurotransmitter gamma-aminobuytric acid (GABA), which operates primarily via chloride-permeable GABA(A) receptor channels. In all developing animal species and brain structures investigated, neurons have a higher intracellular chloride concentration at an early stage leading to an efflux of chloride and excitatory actions of GABA in immature neurons. This triggers sodium spikes, activates voltage-gated calcium channels, and acts in synergy with NMDA channels by removing the voltage-dependent magnesium block. GABA signaling is also established before glutamatergic transmission, suggesting that GABA is the principal excitatory transmitter during early development. In fact, even before synapse formation, GABA signaling can modulate the cell cycle and migration. The consequence of these rules is that developing networks generate primitive patterns of network activity, notably the giant depolarizing potentials (GDPs), largely through the excitatory actions of GABA and its synergistic interactions with glutamate signaling. These early types of network activity are likely required for neurons to fire together and thus to "wire together" so that functional units within cortical networks are formed. In addition, depolarizing GABA has a strong impact on synaptic plasticity and pathological insults, notably seizures of the immature brain. In conclusion, it is suggested that an evolutionary preserved role for excitatory GABA in immature cells provides an important mechanism in the formation of synapses and activity in neuronal networks.
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Affiliation(s)
- Yehezkel Ben-Ari
- Insititut de Neurobiologie de la Méditerranée, Institut National de la Santé et de la Recherche Médicale U. 29, Marseille, France.
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Galanopoulou AS. Developmental patterns in the regulation of chloride homeostasis and GABA(A) receptor signaling by seizures. Epilepsia 2007; 48 Suppl 5:14-8. [PMID: 17910576 DOI: 10.1111/j.1528-1167.2007.01284.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
GABA(A) receptors have dual functions during development. They depolarize immature neurons but hyperpolarize more mature neurons. This functional switch has been attributed to age-related differences in the relative abundance of cation chloride cotransporters, such as KCC2 and NKCC1, which regulate chloride homeostasis. Certain insults, such as trauma, ischemia, and seizures, if they occur when GABA(A)ergic signaling is hyperpolarizing, such as in the adult brain, can lead to reappearance of the immature, depolarizing synaptic responses to GABA(A) receptor activation. In certain cases, this has been associated with either reduced expression of KCC2 or increase in NKCC1. In epilepsy, the depolarizing effects of GABA(A) receptors have been proposed to be important for the acquisition and/or maintenance of the epileptic state. Using the kainic acid model of status epilepticus, we have studied the effects of repetitive neonatal episodes of status epilepticus on the expression of cation chloride cotransporter KCC2 in the neonatal hippocampus. In contrast to adults, seizures increased KCC2 mRNA expression in the CA3 region of the neonatal hippocampus. The contrasting patterns of regulation of KCC2 by seizures in mature and immature neurons may be one of the age-related factors that protect the neonatal brain against the development of epilepsy.
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Affiliation(s)
- Aristea S Galanopoulou
- Albert Einstein College of Medicine, Department of Neurology and Neuroscience, Bronx, New York, USA
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Farrant M, Kaila K. The cellular, molecular and ionic basis of GABA(A) receptor signalling. PROGRESS IN BRAIN RESEARCH 2007; 160:59-87. [PMID: 17499109 DOI: 10.1016/s0079-6123(06)60005-8] [Citation(s) in RCA: 266] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
GABA(A) receptors mediate fast synaptic inhibition in the CNS. Whilst this is undoubtedly true, it is a gross oversimplification of their actions. The receptors themselves are diverse, being formed from a variety of subunits, each with a different temporal and spatial pattern of expression. This diversity is reflected in differences in subcellular targetting and in the subtleties of their response to GABA. While activation of the receptors leads to an inevitable increase in membrane conductance, the voltage response is dictated by the distribution of the permeant Cl(-) and HCO(3)(-) ions, which is established by anion transporters. Similar to GABA(A) receptors, the expression of these transporters is not only developmentally regulated but shows cell-specific and subcellular variation. Untangling all these complexities allows us to appreciate the variety of GABA-mediated signalling, a diverse set of phenomena encompassing both synaptic and non-synaptic functions that can be overtly excitatory as well as inhibitory.
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Affiliation(s)
- Mark Farrant
- Department of Pharmacology, UCL (University College London), Gower Street, London WC1E 6BT, UK.
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Giorgi FS, Velíšková J, Chudomel O, Kyrozis A, Moshé SL. The role of substantia nigra pars reticulata in modulating clonic seizures is determined by testosterone levels during the immediate postnatal period. Neurobiol Dis 2006; 25:73-9. [PMID: 17011203 PMCID: PMC1661598 DOI: 10.1016/j.nbd.2006.08.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 08/03/2006] [Accepted: 08/20/2006] [Indexed: 11/27/2022] Open
Abstract
GABAergic activation of substantia nigra pars reticulata (SNR) at postnatal day (PN) 15 has sex-specific features on seizure control in vivo and electrophysiological responses in vitro. In males, the GABA(A)-receptor agonist muscimol has proconvulsant effects and induces depolarizing responses. In females, muscimol has no effect on seizures and evokes hyperpolarizing responses. We determined the time period during which sex hormones must be present to produce the sex-specific muscimol effects on seizures and their influence on SNR GABA(A) receptor-mediated postsynaptic currents. Exposure to testosterone or its metabolites (estrogen or dihydrotestosterone) during PN0-2 in females or males castrated at PN0 was sufficient to produce proconvulsant muscimol effects but did not affect the in vitro GABA responses, which remained hyperpolarizing. The data suggest that the PN0-2 period is critical for the development of the seizure-controlling SNR system; the hormonal effect on seizure control is independent from their effect on GABA conductance.
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Affiliation(s)
- Filippo S. Giorgi
- The Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY, USA
- Department of Neurosciences, Section of Neurology, University of Pisa, Pisa, Italy
| | - Jana Velíšková
- The Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY, USA
- the Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY, USA
| | - Ondřej Chudomel
- The Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY, USA
| | - Andreas Kyrozis
- The Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY, USA
- Department of Neurology, University of Athens, Greece
| | - Solomon L. Moshé
- The Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY, USA
- the Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY, USA
- Department of Pediatrics ,Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY, USA
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46
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Galanopoulou AS. Sex- and cell-type-specific patterns of GABAAreceptor and estradiol-mediated signaling in the immature rat substantia nigra. Eur J Neurosci 2006; 23:2423-30. [PMID: 16706849 DOI: 10.1111/j.1460-9568.2006.04778.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The substantia nigra pars reticulata (SNR) is involved in movement and seizure control. In male but not female postnatal day 15 (PN15) rats, GABAA receptor agonists depolarize the SNR neurons and increase the expression of the calcium-regulated gene KCC2 (potassium/chloride cotransporter). Moreover, in PN15 rat SNR, 7beta-estradiol down-regulates KCC2 expression only in the presence of depolarizing GABAA receptor responses. The hypothesis tested here was that GABAA receptors and estradiol also regulate the expression of the phosphorylated form of the transcription factor cAMP responsive element binding protein (phosphoCREB), in PN15 rat SNR and substantia nigra pars compacta (SNC). Rats were injected with muscimol or 17beta-estradiol or their vehicles, and killed 1 h later. Sections were stained with an antibody specific for phosphoCREB alone or counterstained with either tyrosine hydroxylase (TH)- or parvalbumin (PRV)-specific antibodies. Muscimol increased phosphoCREB-ir in male but not in female SN neurons. Using gramicidin perforated patch clamp of PN14-15 SNC neuron, it was shown that muscimol bath application depolarized male SNC neurons but did not significantly alter membrane potential in females. In males, 17beta-estradiol decreased phosphoCREB expression in all studied cell types. In females, 17beta-estradiol did not influence phosphoCREB expression in PRV-ir SNR cells, but increased it in the dopaminergic SN neurons. These data suggest that GABAA receptor activation and estradiol promote the sexual differentiation of the SN in a cell-type-specific manner, by influencing calcium-regulated gene transcription, and therefore promoting the acquisition of sex-specific roles of the SN in movement and seizure control.
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Affiliation(s)
- Aristea S Galanopoulou
- Department of Neurology and Einstein/Montefiore Comprehensive Epilepsy Center, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Kennedy Center Rm 311, Bronx, NY 10461, USA.
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