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Dynamic causal modelling of seizure activity in a rat model. Neuroimage 2016; 146:518-532. [PMID: 27639356 DOI: 10.1016/j.neuroimage.2016.08.062] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/27/2016] [Accepted: 08/30/2016] [Indexed: 11/22/2022] Open
Abstract
This paper presents a physiological account of seizure activity and its evolution over time using a rat model of induced epilepsy. We analyse spectral activity recorded in the hippocampi of three rats who received kainic acid injections in the right hippocampus. We use dynamic causal modelling of seizure activity and Bayesian model reduction to identify the key synaptic and connectivity parameters that underlie seizure onset. Using recent advances in hierarchical modelling (parametric empirical Bayes), we characterise seizure onset in terms of slow fluctuations in synaptic excitability of specific neuronal populations. Our results suggest differences in the pathophysiology - of seizure activity in the lesioned versus the non-lesioned hippocampus - with pronounced changes in excitation-inhibition balance and temporal summation on the lesioned side. In particular, our analyses suggest that marked reductions in the synaptic time constant of the deep pyramidal cells and the self-inhibition of inhibitory interneurons (in the lesioned hippocampus) are sufficient to explain changes in spectral activity. Although these synaptic changes are consistent over rats, the resulting electrophysiological phenotype can be quite diverse.
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Grigoletto J, Oliveira CVD, Grauncke ACB, Souza TLD, Souto NS, Freitas MLD, Furian AF, Santos ARS, Oliveira MS. Rosmarinic acid is anticonvulsant against seizures induced by pentylenetetrazol and pilocarpine in mice. Epilepsy Behav 2016; 62:27-34. [PMID: 27448240 DOI: 10.1016/j.yebeh.2016.06.037] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 06/26/2016] [Accepted: 06/27/2016] [Indexed: 01/01/2023]
Abstract
Epilepsy is a chronic neurological disease characterized by spontaneous recurrent seizures (SRS). Current anticonvulsant drugs are ineffective in nearly one-third of patients and may cause significant adverse effects. Rosmarinic acid is a naturally occurring substance which displays several biological effects including antioxidant and neuroprotective activity. Since oxidative stress and excitotoxicity play a role in the pathophysiology of seizures, we aimed the present study to test the hypothesis that rosmarinic acid displays anticonvulsant and disease-modifying effects. Female C57BL/6 mice received rosmarinic acid (0, 3, 10, or 30mg/kg; p.o.) 60min before the injection of pentylenetetrazol (PTZ, 60mg/kg; i.p.) or pilocarpine (300mg/kg, i.p.). Myoclonic and generalized tonic-clonic seizure latencies and generalized seizure duration were analyzed by behavioral and electroencephalographic (EEG) methods. The effect of acute administration of rosmarinic acid on mice behavior in the open-field, object recognition, rotarod, and forced swim tests was also evaluated. In an independent set of experiments, we evaluated the effect of rosmarinic acid (3 or 30mg/kg, p.o. for 14days) on the development of SRS and behavioral comorbidities in the pilocarpine post-status epilepticus (SE) model of epilepsy. Rosmarinic acid dose-dependently (peak effect at 30mg/kg) increased the latency to myoclonic jerks and generalized seizures in the PTZ model and increased the latency to myoclonic jerks induced by pilocarpine. Rosmarinic acid (30mg/kg) increased the number of crossings, the time at the center of the open field, and the immobility time in the forced swim test. In the chronic epilepsy model, treatment with rosmarinic acid did not prevent the appearance of SRS or behavioral comorbidities. In summary, rosmarinic acid displayed acute anticonvulsant-like activity against seizures induced by PTZ or pilocarpine in mice, but further studies are needed to determine its epilepsy-modifying potential.
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Affiliation(s)
- Jéssica Grigoletto
- Graduate Program in Pharmacology, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | | | | | - Thaíze Lopes de Souza
- Graduate Program in Pharmacology, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | - Naieli Schiefelbein Souto
- Graduate Program in Food and Science Technology, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | | | - Ana Flávia Furian
- Graduate Program in Pharmacology, Federal University of Santa Maria, Santa Maria, RS, Brazil; Graduate Program in Food and Science Technology, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | - Adair Roberto Soares Santos
- Graduate Program in Pharmacology, Federal University of Santa Maria, Santa Maria, RS, Brazil; Laboratory of Neurobiology of Pain and Inflammation, Department of Physiological Sciences, Center of Biological Sciences, Federal University of Santa Catarina, Trindade, Florianopolis 88040-900, SC, Brazil
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González-Reyes S, Santillán-Cigales JJ, Jiménez-Osorio AS, Pedraza-Chaverri J, Guevara-Guzmán R. Glycyrrhizin ameliorates oxidative stress and inflammation in hippocampus and olfactory bulb in lithium/pilocarpine-induced status epilepticus in rats. Epilepsy Res 2016; 126:126-33. [PMID: 27490898 DOI: 10.1016/j.eplepsyres.2016.07.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 06/29/2016] [Accepted: 07/25/2016] [Indexed: 01/09/2023]
Abstract
Glycyrrhizin (GL) is a triterpene present in the roots and rhizomes of Glycyrrhiza glabra that has anti-inflammatory, hepatoprotective and neuroprotective effects. Recently, it was demonstrated that GL produced neuroprotective effects on the postischemic brain as well as on the kainic acid injury model in rats. In addition to this, GL also prevented excitotoxic effects on primary cultures. The aims of the present study were to evaluate GL scavenging properties and to investigate GL's effect on oxidative stress and inflammation in the lithium/pilocarpine-induced seizure model in two cerebral regions, hippocampus and olfactory bulb, at acute time intervals (3 or 24h) after status epilepticus (SE). Fluorometric methods showed that GL scavenged three reactive oxygen species: hydrogen peroxide, peroxyl radicals and superoxide anions. In contrast, GL was unable to scavenge peroxynitrite, hydroxyl radicals, singlet oxygen and 2,2-diphenil-1-picrylhydrazyl (DPPH) radicals suggesting that GL is a weak scavenger. Additionally, administration of GL (50mg/kg, i.p.) 30min before pilocarpine administration significantly suppressed oxidative stress. Moreover, malondialdehyde levels were diminished and glutathione levels were maintained at control values in both cerebral regions at 3 and 24 after SE. At 24h after SE, glutathione S-transferase and superoxide dismutase activity increased in the hippocampus, while both glutathione reductase and glutathione peroxidase activity were unchanged in the olfactory bulb at that time. In addition, GL suppressed the induction of the proinflammatory cytokines interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) in both cerebral regions evaluated. These results suggest that GL confers protection against pilocarpine damage via antioxidant and anti-inflammatory effects.
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Affiliation(s)
- Susana González-Reyes
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
| | - Juan Jair Santillán-Cigales
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
| | | | - José Pedraza-Chaverri
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México (UNAM), México
| | - Rosalinda Guevara-Guzmán
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México.
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Hwang ES, Kim HB, Choi GY, Lee S, Lee SO, Kim S, Park JH. Acute rosmarinic acid treatment enhances long-term potentiation, BDNF and GluR-2 protein expression, and cell survival rate against scopolamine challenge in rat organotypic hippocampal slice cultures. Biochem Biophys Res Commun 2016; 475:44-50. [PMID: 27163641 DOI: 10.1016/j.bbrc.2016.04.153] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 04/28/2016] [Indexed: 12/31/2022]
Abstract
BACKGROUND Rosmarinic acid (RA) is a polyphenolic ester of caffeic acid and is commonly found in the Nepetoideae subfamily of flowering mint plants. Because RA has previously exhibited antioxidant, neuroprotective, and antidepressant-like effects, we evaluated its influences on cellular functions in neuronal cultures. OBJECTIVE To elucidate possible mechanisms of RA, we investigated the influences of acute RA administration on long-term potentiation (LTP), plasticity-related protein expression, and scopolamine-induced cell death in organotypic hippocampal slice cultures. METHODS LTP analysis in organotypic hippocampal slice cultures (OHSCs) was carried out with various ion channel blockers, such as AP5 (10 μM), CNQX (10 μM), niflumic acid (100 μM), and scopolamine (300 μM) in response to RA (1, 10 or 100 μg/mL) treatment. Protein expression and cell death assays in the presence of scopolamine were examined to observe the effects of RA. For LTP analysis, baseline field excitatory postsynaptic potentials (fEPSPs) were recorded in CA1 by a 60-channel multielectrode array (MEA) every min for 40 min before 15 min of high-frequency stimulation (HFS) to the Schaffer collaterals and commissural pathways, followed by a successive 50 min of recording. For protein expression measurements, anti-BDNF and anti-GluR2 antibodies were used for Western blotting assays in whole-hippocampal tissue homogenate. Finally, for cell death assays, OHSCs were exposed to a culture medium containing propidium iodide (PI) for 24 or 48 h, followed by the assessment of cell death by fluorescent image analysis of PI uptake. RESULTS and discussion: Our results indicate that RA treatment enhances fEPSPs following HFS in CA1 synapses at 1 and 10 μg/ml RA, an effect that was inhibited by CNQX and NFA but not by AP5. RA treatment also increases the expression of BDNF and GluR-2 proteins and prevents cell death of scopolamine-exposed OHSCs. Our results suggest the possibility that rosmarinic acid can enhance neural plasticity by modulating glutamatergic signaling pathways, as well as providing neuroprotection with reduced cholinergic activity.
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Affiliation(s)
- Eun-Sang Hwang
- Department of East-West Medical Science, Graduate School of East-West Medical Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 446-701, Republic of Korea
| | - Hyun-Bum Kim
- Department of East-West Medical Science, Graduate School of East-West Medical Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 446-701, Republic of Korea
| | - Ga-Young Choi
- Department of East-West Medicine, Graduate School of East-West Medical Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin 446-701, Republic of Korea
| | - Seok Lee
- Department of East-West Medical Science, Graduate School of East-West Medical Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 446-701, Republic of Korea
| | - Sung-Ok Lee
- Department of Oriental Medicinal Materials and Processing, College of Life Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 446-701, Republic of Korea
| | - SangSeong Kim
- College of Pharmacy, Hanyang University, Hanyangdaehak-ro, Sannok-go, Ansan, Gyenggi-do, 15588, Republic of Korea.
| | - Ji-Ho Park
- Department of East-West Medicine, Graduate School of East-West Medical Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin 446-701, Republic of Korea.
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Song H, Xu L, Zhang R, Cao Z, Zhang H, Yang L, Guo Z, Qu Y, Yu J. Rosemary extract improves cognitive deficits in a rats model of repetitive mild traumatic brain injury associated with reduction of astrocytosis and neuronal degeneration in hippocampus. Neurosci Lett 2016; 622:95-101. [DOI: 10.1016/j.neulet.2016.04.048] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 04/08/2016] [Accepted: 04/21/2016] [Indexed: 10/21/2022]
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