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Kakizaki T, Ohshiro T, Itakura M, Konno K, Watanabe M, Mushiake H, Yanagawa Y. Rats deficient in the GAD65 isoform exhibit epilepsy and premature lethality. FASEB J 2020; 35:e21224. [PMID: 33236473 DOI: 10.1096/fj.202001935r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/27/2020] [Accepted: 11/11/2020] [Indexed: 02/02/2023]
Abstract
GABA is synthesized by glutamate decarboxylase (GAD), which has two isoforms, namely, GAD65 and GAD67, encoded by the Gad2 and Gad1 genes, respectively. GAD65-deficient (Gad2-/- ) mice exhibit a reduction in brain GABA content after 1 month of age and show spontaneous seizures in adulthood. Approximately 25% of Gad2-/- mice died by 6 months of age. Our Western blot analysis demonstrated that the protein expression ratio of GAD65 to GAD67 in the brain was greater in rats than in mice during postnatal development, suggesting that the contribution of each GAD isoform to GABA functions differs between these two species. To evaluate whether GAD65 deficiency causes different phenotypes between rats and mice, we generated Gad2-/- rats using TALEN genome editing technology. Western blot and immunohistochemical analyses with new antibodies demonstrated that the GAD65 protein was undetectable in the Gad2-/- rat brain. Gad2-/- pups exhibited spontaneous seizures and paroxysmal discharge in EEG at postnatal weeks 3-4. More than 80% of the Gad2-/- rats died at postnatal days (PNDs) 17-23. GABA content in Gad2-/- brains was significantly lower than those in Gad2+/- and Gad2+/+ brains at PND17-19. These results suggest that the low levels of brain GABA content in Gad2-/- rats may lead to epilepsy followed by premature death, and that Gad2-/- rats are more severely affected than Gad2-/- mice. Considering that the GAD65/GAD67 ratio in human brains is more similar to that in rat brains than in mouse brains, Gad2-/- rats would be useful for further investigating the roles of GAD65 in vivo.
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Affiliation(s)
- Toshikazu Kakizaki
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Tomokazu Ohshiro
- Department of Physiology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Makoto Itakura
- Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, Japan
| | - Kohtarou Konno
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Hajime Mushiake
- Department of Physiology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Japan
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Mathern GW, Bertram EH. Recurrent limbic seizures do not cause hippocampal neuronal loss: A prolonged laboratory study. Neurobiol Dis 2020; 148:105183. [PMID: 33207277 PMCID: PMC7855788 DOI: 10.1016/j.nbd.2020.105183] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 11/02/2022] Open
Abstract
PURPOSE It remains controversial whether neuronal damage and synaptic reorganization found in some forms of epilepsy are the result of an initial injury and potentially contributory to the epileptic condition or are the cumulative affect of repeated seizures. A number of reports of human and animal pathology suggest that at least some neuronal loss precedes the onset of seizures, but there is debate over whether there is further damage over time from intermittent seizures. In support of this latter hypothesis are MRI studies in people that show reduced hippocampal volumes and cortical thickness with longer durations of the disease. In this study we addressed the question of neuronal loss from intermittent seizures using kindled rats (no initial injury) and rats with limbic epilepsy (initial injury). METHODS Supragranular mossy fiber sprouting, hippocampal neuronal densities, and subfield area measurements were determined in rats with chronic limbic epilepsy (CLE) that developed following an episode of limbic status epilepticus (n = 25), in kindled rats (n = 15), and in age matched controls (n = 20). To determine whether age or seizure frequency played a role in the changes, CLE and kindled rats were further classified by seizure frequency (low/high) and the duration of the seizure disorder (young/old). RESULTS Overall there was no evidence for progressive neuronal loss from recurrent seizures. Compared with control and kindled rats, CLE animals showed increased mossy fiber sprouting, decreased neuronal numbers in multiple regions and regional atrophy. In CLE, but not kindled rats: 1) Higher seizure frequency was associated with greater mossy fiber sprouting and granule cell dispersion; and 2) greater age with seizures was associated with decreased hilar densities, and increased hilar areas. There was no evidence for progressive neuronal loss, even with more than 1000 seizures. CONCLUSION These findings suggest that the neuronal loss associated with limbic epilepsy precedes the onset of the seizures and is not a consequence of recurrent seizures. However, intermittent seizures do cause other structural changes in the brain, the functional consequences of which are unclear.
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Affiliation(s)
- Gary W Mathern
- Division of Neurosurgery, The Mental Retardation Research Center, United States of America; Division of Neurosurgery, The Brain Research Institute, United States of America; University of California, Los Angeles, Los Angeles, California, United States of America
| | - Edward H Bertram
- Department of Neurology, University of Virginia, Charlottesville, Virginia, United States of America.
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Effects of enriched environment in spatial learning and memory of immature rats submitted to early undernourish and seizures. Int J Dev Neurosci 2012; 30:363-7. [DOI: 10.1016/j.ijdevneu.2012.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 04/11/2012] [Accepted: 04/11/2012] [Indexed: 01/27/2023] Open
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Chen C, Lang S, Xu G, Liu X, Zuo P. Effects of topiramate on seizure susceptibility in kainate-kindled rats: Involvement of peripheral-type benzodiazepine receptors. Seizure 2008; 17:358-63. [DOI: 10.1016/j.seizure.2007.11.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Revised: 09/26/2007] [Accepted: 11/20/2007] [Indexed: 11/27/2022] Open
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Shepherd TM, Wirth ED, Thelwall PE, Chen HX, Roper SN, Blackband SJ. Water diffusion measurements in perfused human hippocampal slices undergoing tonicity changes. Magn Reson Med 2003; 49:856-63. [PMID: 12704768 DOI: 10.1002/mrm.10456] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Diffusion MRI has the potential to probe the compartmental origins of MR signals acquired from human nervous tissue. However, current experiments in human subjects require long diffusion times, which may confound data interpretation due to the effects of compartmental exchange. To investigate human nervous tissue at shorter diffusion times, and to determine the relevance of previous diffusion studies in rat hippocampal slices, water diffusion in 20 perfused human hippocampal slices was measured using a wide-bore 17.6-T magnet equipped with 1000-mT/m gradients. These slices were procured from five patients undergoing temporal lobectomy for epilepsy. Tissue viability was confirmed with electrophysiological measurements. Diffusion-weighted water signal attenuation in the slices was well-described by a biexponential function (R(2) > 0.99). The mean diffusion parameters for slices before osmotic perturbation were 0.686 +/- 0.082 for the fraction of fast diffusing water (F(fast)), 1.22 +/- 0.22 x 10(-3) mm(2)/s for the fast apparent diffusion coefficient (ADC), and 0.06 +/- 0.02 x 10(-3) mm(2)/s for the slow ADC. Slice perturbations with 20% hypotonic and 20% hypertonic artificial cerebrospinal fluid led to changes in F(fast) of -8.2% and +10.1%, respectively (ANOVA, P < 0.001). These data agree with previous diffusion studies of rat brain slices and human brain in vivo, and should aid the development of working models of water diffusion in nervous tissue, and thus increase the clinical utility of diffusion MRI.
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Affiliation(s)
- Timothy M Shepherd
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610, USA.
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Caplan R, Siddarth P, Mathern G, Vinters H, Curtiss S, Levitt J, Asarnow R, Shields WD. Developmental outcome with and without successful intervention. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2002; 49:269-84. [PMID: 12040897 DOI: 10.1016/s0074-7742(02)49017-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
A review of the literature on the developmental outcome of medically and surgically treated symptomatic infantile spasms (IS) indicates that poor seizure control, severe mental retardation, and marked behavioral disorders are found at long-term outcome of symptomatic IS. The 2-year outcome findings of the UCLA Pediatric Epilepsy Surgery Research Group in children with symptomatic infantile spasms and in children with early onset intractable symptomatic epilepsy other than IS (non-IS) demonstrate impaired development of cognition, language, and social communication despite improved seizure control. The social communication deficits of these children are similar to those found in autistic children. Finally, the underlying pathology of the resected brain, rather than ongoing seizures and seizure type, plays an important role in development of the remaining brain tissue and the outcome of early onset symptomatic IS and non-IS.
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Affiliation(s)
- Rochelle Caplan
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, California 90095, USA
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Huang LT, Holmes GL, Lai MC, Hung PL, Wang CL, Wang TJ, Yang CH, Liou CW, Yang SN. Maternal deprivation stress exacerbates cognitive deficits in immature rats with recurrent seizures. Epilepsia 2002; 43:1141-8. [PMID: 12366727 DOI: 10.1046/j.1528-1157.2002.14602.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Maternal deprivation is stressful for the neonate. The aim of this study was to investigate the short- and long-term effects of maternal separation on recurrent seizures in the developing brain. METHODS Rats were divided into four groups according to whether the rat pups were treated with maternal deprivation from postnatal day 2 (P2) to P9 or neonatal seizures induced by intraperitoneal (i.p.) injection of pentylenetetrazol (PTZ) from P10 to P14. Rats in the control group received saline i.p. injection from P10 to P14; rats in the isolation group underwent daily separation from their dams from P2 to P9; rats in the PTZ-treated group were subjected to PTZ-induced recurrent seizures from P10 to P14; rats in the isolation plus PTZ-treated group were subjected to maternal deprivation from P2 to P7 followed by serial seizures from P10 to P14. In addition, subsets of rats at P15 were killed and the brains assessed for acute neuronal degeneration. Visual-spatial memory test using the Morris water maze task was performed at P80. After testing, the hippocampus was evaluated for histologic lesions and cyclic adenosine monophosphate (cAMP)-responsive element-binding protein phosphorylation at serine-133 (pCREBSer-133), an important transcription factor underlying learning and memory. RESULTS All rats given PTZ developed recurrent seizures. After PTZ administration, rats with a history of maternal deprivation had more intense impairment than did rats with maternal deprivation and neonatal seizures than those without deprivation. Neuronal degeneration was most prominent in the rats exposed to maternal deprivation plus recurrent seizures. Rats receiving maternal deprivation or PTZ-induced recurrent seizures exhibited only spatial deficits, but no morphologic changes in the hippocampus. However, rats with maternal deprivation plus PTZ-induced recurrent seizures exhibited worse visual-spatial learning compared with rats with either isolation or PTZ-induced recurrent seizures alone. The levels of pCREBSer-133 may play a role in the decrease in the hippocampus from the rats subjected to maternal deprivation and/or PTZ-induced recurrent seizures, as compared with rats exposed to vehicle-control saline. These results indicate that repeated maternal deprivation can exacerbate long-term cognitive deficits resulting from neonatal seizures. In addition, impaired phosphorylation of CREBSer-133. CONCLUSIONS Repeated maternal deprivation stress has synergistic effects with recurrent seizures in inducing neurologic damage in the developing brain.
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Affiliation(s)
- Li-Tung Huang
- Department of Pediatrics and Neurology, Chang Gung Memorial Hospital, Kaohsiung, Taiwan
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Mathern GW, Adelson PD, Cahan LD, Leite JP. Hippocampal neuron damage in human epilepsy: Meyer's hypothesis revisited. PROGRESS IN BRAIN RESEARCH 2002; 135:237-51. [PMID: 12143344 DOI: 10.1016/s0079-6123(02)35023-4] [Citation(s) in RCA: 192] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Whether hippocampal neuron loss and/or hippocampal sclerosis is the 'cause' or 'consequence' of seizures has been a fundamental question in human epilepsy studies for over a century. To address this question, this study examined hippocampal specimens from temporal lobe epilepsy patients (TLE; n = 572) and those with extra-temporal seizures and pathologies (n = 73) for qualitative signs of hippocampal sclerosis and quantitative neuron loss using cell counting techniques. Patients were additionally classified based on pathological substrate, and history of an initial precipitating injury (IPI). Results showed that: (1) Hippocampal sclerosis was strongly linked with an IPI in both TLE and extra-temporal seizure patients. (2) In TLE cases, IPIs showed an early age preference and often involved seizures, but IPIs were not age dependent and older IPI cases showed sclerosis that was indistinguishable from younger IPI patients. (3) In TLE patients, longer seizure durations were associated with decreased neuronal densities in all hippocampal subfields. The decrease was independent of the neuron loss linked with IPIs, it occurred in all pathological groups, it occurred over 30 years or more, and was not a consequence of aging. (4) Intractable seizures in the young human hippocampus were not associated with neuronal damage, but were linked with decreased postnatal granule cell development and aberrant axon sprouting. These results support the concept that hippocampal sclerosis is likely an acquired pathology, and most of the neuronal loss occurs with the IPI. In addition, there is progressive hippocampal damage from intractable TLE regardless of pathology. Hence, hippocampal neuron loss can be the 'consequence' of repeated limbic seizures over 30 years or more, but is unlikely to 'cause' hippocampal sclerosis unless there is also an IPI.
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Affiliation(s)
- Gary W Mathern
- Division of Neurosurgery, Mental Retardation Research Center, Brain Research Institute, University of California, Los Angeles, CA 90095-1769, USA.
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Hung PL, Lai MC, Yang SN, Wang CL, Liou CW, Wu CL, Wang TJ, Huang LT. Aminophylline exacerbates status epilepticus-induced neuronal damages in immature rats: a morphological, motor and behavioral study. Epilepsy Res 2002; 49:218-25. [PMID: 12076843 DOI: 10.1016/s0920-1211(02)00030-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Adenosine is an endogenous modulator that has an inhibitory effect on neuronal activity. The aim of this work was to investigate the role of aminophylline, an adenosine receptor antagonist, on the long-term effects of status epilepticus (SE) in the developing brain. Four groups of rats at the postnatal age of 12 days were intraperitoneally administered with saline, aminophylline (50 mg/kg), lithium-pilocarpine (Li-PC) (3 mEq/kg-60 mg/kg), and Li-PC plus aminophylline, respectively. The four groups were tested for spatial memory using the Morris water maze task at P80 and motor performance by the Rotarod test at P100. The brains were then analyzed with cresyl violet stain for histological lesions and evaluated for mossy fiber sprouting with the Timm stain. At the acute stage, all rats subjected to Li-PC developed SE and no seizures were elicited in the saline-treated or aminophylline-treated rats. The seizure duration was longer in the Li-PC plus aminophylline group (346.9+/-32.7 min) as compared with that in the Li-PC group (265.2+/-9.8 min). The difference of mortality was not significant. Rats without seizures exhibited no motor imbalance, spatial deficits, or morphological changes. The rats with Li-PC-induced SE demonstrated spatial memory deficits without motor incoordination or morphological changes. However, the rats subjected to Li-PC plus aminophylline exhibited motor impairment and morphological changes, including neuronal cell loss in CA1 area and increased mossy fiber sprouting in CA3 area. In addition, the rats of Li-PC plus aminophylline had greater spatial memory deficits than that seen in rats with Li-PC. We concluded that an adenosine receptor antagonist, such as aminophylline, had synergistic effects on the SE-induced long-term deficit of cognition and motor performance in the developing brain. The present study may provide experimental evidence and lead to novel therapeutic interventions.
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Affiliation(s)
- Pi-Lien Hung
- Department of Pediatrics, Chang Gung Memorial Hospital, 123, Ta-Pei RD, Niao-Sung, Kaohsiung 833, Taiwan, ROC
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Huang LT, Liou CW, Yang SN, Lai MC, Hung PL, Wang TJ, Cheng SC, Wu CL. Aminophylline aggravates long-term morphological and cognitive damages in status epilepticus in immature rats. Neurosci Lett 2002; 321:137-40. [PMID: 11880191 DOI: 10.1016/s0304-3940(01)02467-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Here, we investigated whether aminophylline, an adenosine receptor antagonist used usually as a treatment for premature apnea, had synergistic effects on status epilepticus in the developing brain. On postnatal day 14 (P14), four groups of rats intraperitoneally received saline, aminophylline, lithium--pilocarpine (Li-PC), and Li-PC plus aminophylline, respectively. Subsequently, the Morris water maze task was performed at P80. The brains were then analyzed with cresyl violet stain for histological lesions and evaluated for mossy fiber sprouting with the Timm stain. No seizures were elicited in the saline-treated or aminophylline-treated rats. Both the Li-PC-treated and aminophylline plus Li-PC-treated rats exhibited seizures and there was no significant difference in mortality between the two groups. More interestingly, as in adulthood (P80), aminophylline aggravated the spatial deficits and histological damages seen in Li-PC-treated rats. In summary, this present study suggests that the use of adenosine receptor antagonists, such as aminophylline, exacerbates seizure-induced damage in the developing brain.
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Affiliation(s)
- Li-Tung Huang
- Department of Pediatrics, Chang Gung Memorial Hospital, 123, Ta-Pei Road, Niao-Sung, Kaohsiung, Taiwan.
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