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Objective At present, studies on the calcium sensing receptor (CaSR) in the pathogenesis of epilepsy are carried out in animal models in vivo and in single cells cultured in vitro. This study was to investigate the expression of CaSR and its relationship with the MAPK pathway in the rat model of epilepsy.Methods The neurons and cardiomyocytes of 3-day-old Wistar rats were cultured for 10 days and randomly divided into groups A (control), B (magnesium-free), C (magnesium free+spermine), D (magnesium free+calhex231), and E (magnesium free+spermine+calhex231). The model of epilepsy was made by abnormal discharge of the neurons induced by coculturing magnesium-free extracellular fluid with cardiomyocytes. The morphological changes of the cells were observed by HE staining and transmission electron microscopy, their survival rate detected by MTT, and the expressions of the CaSR, Bcl-2, P-ERK, P-JNK and P-P38 proteins in the cocultured cells determined by Western blot.Results Compared with the cells in group B, those in group C were swollen and broken with nuclear fragmentation, those in group D showed a relative integrity, and those in group E were also swollen and broken but improved in comparison with those in group C. The survival rates of the cells were (61.08±15.44)%, (82.80±14.37)% and (82.04±17.37)% in groups C, D and E, respectively, all significantly lower than in A (\[100.00±0.00\]%, P<0.01) and B (\[88.88±9.85\]%, P<0.01). The expression of CaSR was markedly higher in group B than in A (\[0.73±0.19\] vs \[0.45±0.12\], P<0.01) but lower than in C (1.32±0.15) and E (1.19±0.12) (P<0.01). The expression levels of Bcl-2 and P-ERK were remarkably lower in group B than in A but higher than in C (P<0.01), and those of P-JNK and P-P38 significantly higher in group B than in A and lower than in C and E (P<0.05).Conclusion Magnesium-free extracellular fluid can damage neurons and cardiomyocytes, increase the expression of CaSR, participate in the MAPK signaling pathway, and mediate the apoptosis of neurons and cardiomyocytes, while CaSR inhibitors can relieve the CaSR agonist-induced damage to the cells.
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Objective To explore the effect of liensinine on cortical EEG of epileptic rats induced by lithium chloride-pilocarpine,and investigate the effective spectrum of liensinine on epilepsy.Methods 32 SD rats were randomly divided into four groups:low dose of liensinine group(2.5 mg/mL, 10μL),high dose of liensinine group(5 mg/mL,10μL),the normal saline group(10μL)which was negative control group,levetiracetam group (100 mg/mL,10μL)which was positive control group,8 rats in each group.Electrocorticogram of rats was recorded after chloride lithium-pilocarpine model was induced.The anesthetic rats were fixed on stereotaxic apparatus after the epilepsy model was confirmed by ethology.A trochar was put into the left lateral ventricle.Rats were implanted with epidural recording electrodes.After the cortical EEG was recorded about 30 minutes, liensinine (at concentration of 2.5,5 mg/mL),levetiracetam and 0.9% sodium chloride was injected into lateral ventricle.Electrocorticogram was recorded about 150 minutes again.The frequency of epileptic discharge was observed every 30 minutes.The differences of frequency in the same group and the different change of frequency between groups at the same period were compared.Results The frequency of epileptic discharge decreased in low dose of liensinine group,high dose of liensinine group and levetiracetam group after administration ,there was significantly statistical difference in low dose of liensinine group after administration about 60 minutes(P<0.01 ),there was significant statistics difference in high dose of liensinine group after administration about 30 minutes(P<0.01),and the same change in levetiracetam group within 30 minutes after administration(P<0.01);the change of frequency of epileptic discharge was no significantly statistical difference between pro-and post-administration in the normal saline control group.The difference of the frequency change in epileptic discharge at the same period between liensinine group and levetiracetam group was observed ,there was statistic difference between low dose of liensinine group and levetiracetam group at the period of thirty to sixty minutes after administration,there was no statistic difference at other periods;there was no statistic difference between high dose of liensinine group and levetiracetam group at every period.Conclusion Liensinine could inhibit the epileptic discharges in acute model of epileptic rats induced by chloride lithium-pilocarpine.
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ObjectiveTo investigate the mechanisms and the effects of magnesium Valproate on the expressions of the kinin B1 and B2 receptors in the hippocampus of the juvenile rats submitted to pilocarpine model of epilepsy.Methods 35 healthy Wistar juvenile rats were randomly divided into six groups,that is the model groups:Ⅰ group,Ⅱ group,Ⅲ group,and intraperitoneal injection of saline water control groups:Ⅰ a group,Ⅱ a group,Ⅲ a group,after succession of 15 rats to kindle to establish the model of epilepsy by pilocarpine.To collect hippocampus tissue after the rats were to put to death,and to compared the expression levels of kinin B1 and B2 receptor mRNA by RT-PCR and western blot in the hippocampus of rats.ResultsBy treated with magnesium valproate,kinin B1 receptor mRNA (0.38 ± 0.051 ) and protein expressions(0.58 ± 0.057 ) decreased and kinin B2 receptor mRNA (0.48 ±0.056 ) and protein expressions(0.48 ± 0.044 ) increased in Ⅰ group,compared with that (0.76 ±0.068,0.89 ± 0.034;0.28 ± 0.034,0.32 ± 0.039 ) of Ⅰ a group(P ＜ 0.05 ).Compared with control group,there were more significant upregulation of kinin B1 receptor mRNA and protein expressions (P＜0.05) in the Ⅰ and the Ⅱ groups and there were no alteration in Ⅲ group.The expressional levels of B2 receptor mRNA and protein were upregulated in the Ⅰ,Ⅱ and Ⅲ groups.ConclusionThe kinin B1 and B2 receptor may play a role in the onset and maintenance of epilepsy.The magnesium valproate increased the expressional levels of kinin B2 receptor,and decreased the expressional levels of kinin B1 receptor.
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@#ObjectiveTo investigate and compare the behavioral changes, neuron loss of hippocampus and mossy fiber sprouting between pilocarpine-induced status epilepticus (SE) model and pentylenetetrazole (PTZ) kindling model in rats.MethodsAfter two different epilepsy models were made, Vedio was adopted to observe the behavioral changes. Nissl staining and Neo-timms' staining were separately used to observe and compare the neuron loss of hippocampus and mossy fiber sprouting in the dentate gyrus (DG) at different time points during epileptogenisis.ResultsNo recurrent spontaneous seizure, no neuron loss and no mossy fiber sprouting were found in PTZ kindling model; whereas obvious neuron loss was found in CA1, CA3 of hippocampus and hilus of DG, and mossy fiber sprouting were found in pilocarpine model in parallel with recurrent spontaneous seizures. ConclusionPTZ kindling model resembles absence epilepsy in human, while pilocarpine-induced status epilepticus model resembles chronic temporal epilepsy in human. Neuron loss and mossy fiber sprouting may play an important role in epileptogenisis. Pilocarpine-induced epilepsy model can be regarded as an ideal chronic temporal epilepsy model.
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Objective To investigate the changes and possible mechanisms of the expressions of metabolic pattern glutamic acid receptor 1(mGluR1) and mGluR3 in hippocampus of juvenile rats submitted to lithium chloride-pilocarpine induced model of epilepsy in 6 h,5 d,60 d after status epilepticus(SE) onset.Methods Seizures were induced in the juvenile rats with lithium and pilocarpine injected intraperito-neally,and behavioral changes and EEG were observed.Eighteen SD juvenile rats with SE were randomly divided into following groups: groupⅠ,in which the rats were killed at 6 h after SE onset(6 h SE),group Ⅱ,in which the animals were killed during the seizure-free period(5 days after SE onset),and group Ⅲ,in which the animals were killed in 60 days after SE induction(period of spontaneous recurrent seizures).And intraperitoneal injection of saline water control groups were divided into: groupⅠa,group Ⅱa and group Ⅲa.The hippocampus tissues after the rats were put to death were collected,the expressions of mGluR1 and mGluR3 mRNA were detected by reverse transcriptase polymerase chain reaction(RT-PCR) in the hippocampus of juvenile rats.Results EEG of rats in group Ⅰ were abnormal,but normal in groupⅡ,and 5(83%) cases of the juvenile rats in group Ⅲ manifested dissemination of sharp waves,spikes or spike wave.The saline control group did not spontaneously attack.There was more significant upregulation of mGluR1 mRNA expression(Pa0.05).The expressional levels of mGluR3 mRNA were upregulated in groupⅠ,group Ⅱ and group Ⅲ(Pa
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Recently published data (Baran et al., Neurosignals 2004; 13: 290-7) have shown significantly increased activity of glutamic acid decarboxylase, the neuronal marker for gamma-aminobutyrate (GABA)-neurons, in the frontal cortex of rat brains, 6 months after kainic acid (KA) injection. In present study glutamate and GABA levels in the frontal cortex of rats in the KA (10 mg/kg, subcutaneously)-induced spontaneous recurrent seizure model of epilepsy, 6 months after the initial KA-induced seizures, were investigated. Six months after KA injection there was found a slightly reduced glutamate level in the frontal cortex (89.7 % of control), whereas the GABA level was moderately increased (119.6 % of control). The ratio GABA:glutamate level was significantly increased in the frontal cortex (134.5 % of control; P<0.001). Obtained data would indicate an enhancement of GABAergic activities in the frontal cortex in the chronic KA epileptic model. Interaction within GABAergic parameters, thus the GABAA receptors, the GABAB receptors, glutamate and GABA transporters may play a role in the modulation but also in the exertion of epileptic events in chronic KA epileptic model, which needs to be clarified.
Subject(s)
Animals , Rats , Epilepsy , Epilepsy, Temporal Lobe , gamma-Aminobutyric Acid , Glutamates , Kainic Acid , Neurology , Neuroprotective Agents , Prefrontal Cortex , Receptors, GABA , Receptors, Kainic Acid , Rats , Rats, Sprague-DawleyABSTRACT
@#The epilepsy symptom and the pia microcirculatory blood flow volume (PMBFV) were investigated in epilepsy rat model induced by strychnine and the changes after treatment by using faradized frequency spectrum therapeutic equipment were observed. The epilepsy symptom was improved and the PMBFV increased after treatment. The convulsion seizure time was delayed, the seizure frequency and convulsion time were reduced, and the epilepsy even was not appeared in some cases. Results suggested that this improvement might be related to the change of PMBFV.
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BACKGROUND: The purpose of this study is to evaluate the synaptic reorganization and pattern of mossy fiber sprouting as a pathologic mechanism of chronic seizure in pilocarpine epilepsy model through histological alterations of hippocampus. METHOD: Sprague-Dawley, a sensitively damaged by pilocarpine stimulation, served as a experimental group(n=20). And the same dose of saline injected rats were served as a control group(n=10). They were implanted depth electrode in the hippocampus by a stereotaxic surgery, and injected pilocarpine 300mg/Kg intraperitoneally. They produced status epilepticus and the survival rats were monitored by a video-EEG monitoring system whether the spontaneous recurrent seizures occurring for more than 4 weeks. If more than 3 times spontaneous recurrent seizures were identified, then the rat hippocampus was examined by light microscope. RESULT: The pilocarpine injected group produced acute limbic seizure and developed to status epilepticus. The survival rats(n=10) became to chronic epilepsy state after silent period of everage 16.5 days. H&E staining demonstrated that loss of hilar polymorphic cell with ischemic changes and destruction of CA1 with damages of pyramidal cells in hippocampal subfields. Timm stains showed mossy fiber synatic reorganization in the supragranular and intragranular layer of dentate gyrus and infrapyramidal layer of CA3 hippocampal subfieid in pilocarpine induce seizure rats. CONCLUSION: These results suggest that chronic seizures in the pilocarpine epilepsy model is largely due to mossy fiber synatic reorganization, a consequence of supragranular mossy fiber sprouting. But intragranular and infrapyramidal axonal sprouting might have parts of role in synaptic reorganization. Additional research is required to determine the various patterns of axonal sprouting.