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Rodrigues AM, Silva DB, Miranda MF, Braga da Silva SC, Canton Santos LE, Scorza FA, Scorza CA, Moret MA, Guimarães de Almeida AC. The Effect of Low Magnesium Concentration on Ictal Discharges In A Non-Synaptic Model. Int J Neural Syst 2020; 31:2050070. [PMID: 33357154 DOI: 10.1142/s0129065720500707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Magnesium (Mg[Formula: see text] is an essential mineral for several cellular functions. The concentration of this ion below the physiological concentration induces recurrent neuronal discharges both in slices of the hippocampus and in neuronal cultures. These epileptiform discharges are initially sensitive to the application of [Formula: see text]-methyl-D-aspartate (NMDA) receptor antagonists, but these antagonists may lose their effectiveness with prolonged exposure to low [Mg[Formula: see text]], when extracellular Ca[Formula: see text] reduction occurs, typical of ictal periods, indicating the absence of synaptic connections. The study herein presented aimed at investigating the effect of reducing the [Mg[Formula: see text]] during the induction of Nonsynaptic Epileptiform Activities (NSEA). As an experimental protocol, NSEA were induced in rat hippocampal dentate gyrus (DG), using a bath solution containing high-K[Formula: see text] and zero-added-Ca[Formula: see text]. Additionally, computer simulations were performed using a mathematical model that represents electrochemical characteristics of the tissue of the DG granular layer. The experimental results show that the reduction of [Mg[Formula: see text]] causes an increase in the duration of the ictal period and a reduction in the interictal period, intensifying epileptiform discharges. The computer simulations suggest that the reduction of the Mg[Formula: see text] level intensifies the epileptiform discharges by a joint effect of reducing the surface charge screening and reducing the activity of the Na/K pump.
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Affiliation(s)
- Antônio Márcio Rodrigues
- Laboratório de Neurociência, Experimental e Computacional, Departamento de Engenharia de, Biossistemas Universidade Federal de São João del-Rei, Pr. Dom Helvécio, 74, 36.301-160 São João del-Rei, MG, Brazil
| | - Delmo Benedito Silva
- Laboratório de Neurociência, Experimental e Computacional, Departamento de Engenharia de, Biossistemas Universidade Federal de São João del-Rei, Pr. Dom Helvécio, 74, 36.301-160 São João del-Rei, MG, Brazil
| | - Maísa Ferreira Miranda
- Laboratório de Neurociência, Experimental e Computacional, Departamento de Engenharia de, Biossistemas Universidade Federal de São João del-Rei, Pr. Dom Helvécio, 74, 36.301-160 São João del-Rei, MG, Brazil
| | - Silvia Cristina Braga da Silva
- Laboratório de Neurociência, Experimental e Computacional, Departamento de Engenharia de, Biossistemas Universidade Federal de São João del-Rei, Pr. Dom Helvécio, 74, 36.301-160 São João del-Rei, MG, Brazil
| | - Luiz Eduardo Canton Santos
- Laboratório de Neurociência, Experimental e Computacional, Departamento de Engenharia de, Biossistemas Universidade Federal de São João del-Rei, Pr. Dom Helvécio, 74, 36.301-160 São João del-Rei, MG, Brazil
| | - Fulvio Alexandre Scorza
- Disciplina de Neurociência, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Carla Alessandra Scorza
- Disciplina de Neurociência, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Marcelo A Moret
- UNEB - Rua Silveira Martins, 2555, Cabula 41150-000 Salvador, Bahia, Brazil
| | - Antônio-Carlos Guimarães de Almeida
- Laboratório de Neurociência, Experimental e Computacional, Departamento de Engenharia de, Biossistemas Universidade Federal de São João del-Rei, Pr. Dom Helvécio, 74, 36.301-160 São João del-Rei, MG, Brazil
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Santos LEC, Rodrigues AM, Lopes MR, Costa VDC, Scorza CA, Scorza FA, Cavalheiro EA, Almeida ACG. Long-term alcohol exposure elicits hippocampal nonsynaptic epileptiform activity changes associated with expression and functional changes in NKCC1, KCC2 co-transporters and Na +/K +-ATPase. Neuroscience 2017; 340:530-541. [PMID: 27871891 DOI: 10.1016/j.neuroscience.2016.11.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 11/04/2016] [Accepted: 11/10/2016] [Indexed: 01/22/2023]
Abstract
Nonsynaptic mechanism changes, particularly the enhancement of NKCC1 expression in the dentate gyrus (DG) after 4weeks of ethanol consumption, motivate the present work, in which rats were submitted to a period of chronic consumption (12weeks). Four groups of six animals (6-week-old male Wistar rats) were formed, including the control (C), ethanol 1 (E1), ethanol 2 (E2) and ethanol 3 (E3) groups. The rats in the E1, E2 and E3 groups were treated daily with a 30% v/v solution of ethanol, administered via oral gavage (1.0, 2.0 and 3.0g/kg, respectively). Nonsynaptic epileptiform activities (NEA) were induced by means of the zero-Ca2+ and high-K+ model using hippocampal slices and were recorded in the DG. The presence of NKCC1, KCC2, α1-Na+/K+-ATPase and GFAP immunoreactivity was analyzed. The results demonstrate that alcohol consumption changes NEA, and these changes are more prominent at the lower dosage. An increase in the DC shifts associated with epileptiform discharges was present with the low dose. This increase was correlated with the increment of NKCC1 expression. Confocal microscopy images indicate the NKCC1 increase was pronounced in the initial axonal segment of granule cells. The blockage of these cotransporters during NEA induction with bumetanide suppressed the DC shift increase and diminished all parameters of NEA that were quantified for all groups treated with ethanol. Therefore, the increase in NKCC1 expression and the effective activity of this cotransporter, which were observed in the treated groups, suggest that drugs that act for block NKCC1 represent promising strategies for diminishing the effects of alcohol damage on the brain.
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Affiliation(s)
- Luiz E C Santos
- Laboratório de Neurociência Experimental e Computacional, Departamento de Engenharia de Biossistemas, UFSJ, Brazil
| | - Antônio M Rodrigues
- Laboratório de Neurociência Experimental e Computacional, Departamento de Engenharia de Biossistemas, UFSJ, Brazil
| | - Mariana R Lopes
- Laboratório de Neurociência Experimental e Computacional, Departamento de Engenharia de Biossistemas, UFSJ, Brazil
| | - Victor D C Costa
- Laboratório de Neurociência Experimental e Computacional, Departamento de Engenharia de Biossistemas, UFSJ, Brazil
| | - Carla A Scorza
- Disciplina de Neurologia Experimental, Escola Paulista de Medicina, Unifesp, Brazil
| | - Fulvio A Scorza
- Disciplina de Neurologia Experimental, Escola Paulista de Medicina, Unifesp, Brazil
| | - Esper A Cavalheiro
- Disciplina de Neurologia Experimental, Escola Paulista de Medicina, Unifesp, Brazil
| | - Antônio-Carlos G Almeida
- Laboratório de Neurociência Experimental e Computacional, Departamento de Engenharia de Biossistemas, UFSJ, Brazil.
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Nogueira GS, Santos LEC, Rodrigues AM, Scorza CA, Scorza FA, Cavalheiro EA, de Almeida ACG. Enhanced nonsynaptic epileptiform activity in the dentate gyrus after kainate-induced status epilepticus. Neuroscience 2015; 303:59-72. [PMID: 26141843 DOI: 10.1016/j.neuroscience.2015.06.057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 05/28/2015] [Accepted: 06/25/2015] [Indexed: 11/29/2022]
Abstract
Understanding the mechanisms that influence brain excitability and synchronization provides hope that epileptic seizures can be controlled. In this scenario, non-synaptic mechanisms have a critical role in seizure activity. The contribution of ion transporters to the regulation of seizure-like activity has not been extensively studied. Here, we examined how non-synaptic epileptiform activity (NEA) in the CA1 and dentate gyrus (DG) regions of the hippocampal formation were affected by kainic acid (KA) administration. NEA enhancement in the DG and suppression in area CA1 were associated with increased NKCC1 expression in neurons and severe neuronal loss accompanied by marked glial proliferation, respectively. Twenty-four hours after KA, the DG exhibited intense microglial activation that was associated with reduced cell density in the infra-pyramidal lamina; however, cellular density recovered 7 days after KA. Intense Ki67 immunoreactivity was observed in the subgranular proliferative zone of the DG, which indicates new neuron incorporation into the granule layer. In addition, bumetanide, a selective inhibitor of neuronal Cl(-) uptake mediated by NKCC1, was used to confirm that the NKCC1 increase effectively contributed to NEA changes in the DG. Furthermore, 7 days after KA, prominent NKCC1 staining was identified in the axon initial segments of granule cells, at the exact site where action potentials are preferentially initiated, which endowed these neurons with increased excitability. Taken together, our data suggest a key role of NKCC1 in NEA in the DG.
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Affiliation(s)
- G S Nogueira
- Laboratório de Neurociência Experimental e Computacional, Departamento de Engenharia de Biossistemas, Universidade Federal de São João del-Rei, São João del-Rei, Brazil.
| | - L E C Santos
- Laboratório de Neurociência Experimental e Computacional, Departamento de Engenharia de Biossistemas, Universidade Federal de São João del-Rei, São João del-Rei, Brazil.
| | - A M Rodrigues
- Laboratório de Neurociência Experimental e Computacional, Departamento de Engenharia de Biossistemas, Universidade Federal de São João del-Rei, São João del-Rei, Brazil.
| | - C A Scorza
- Disciplina de Neurociência, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
| | - F A Scorza
- Disciplina de Neurociência, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
| | - E A Cavalheiro
- Disciplina de Neurociência, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
| | - A-C G de Almeida
- Laboratório de Neurociência Experimental e Computacional, Departamento de Engenharia de Biossistemas, Universidade Federal de São João del-Rei, São João del-Rei, Brazil.
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Rodrigues AM, Santos LEC, Covolan L, Hamani C, de Almeida ACG. pH during non-synaptic epileptiform activity—computational simulations. Phys Biol 2015; 12:056007. [DOI: 10.1088/1478-3975/12/5/056007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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