| Epilepsy disease is one of the oldest known neurological disorders and one of the most common severe encephalopathy.Its incidence is very high,clinical symptoms and pathogenic cause is not single,and has a variety of risk factors and strong genetic tendency.Existing antiepileptic drugs may suppress seizures in two-thirds of people,but a considerable number of patients are not sensitive to existing drugs.Therefore,the exploration of new antiepileptic drugs has been a focus of research.There are many mechanisms in epilepsy,including abnormal neuronal firing,cell apoptosis,neuroinflammatory response,excitatory and inhibitory neurotransmitter imbalance,and abnormal neural network remodeling.Among them,excessive synchronous abnormal firing in neuronal populations is an important cause of seizures.Thus,the historical focus of epilepsy research is on nerve centers.It is well known that the hippocampus is the brain region most closely linked to epilepsy disease and is involved in seizures,while pyramidal neurons in the CA1 and CA3 regions are the main cell types in the hippocampus.We we chose to study pyramidal neurons in the CA1 region of the hippocampus.Nicorandil is a drug that has both nitrate-like and adenosine triphosphate(ATP)-sensitive potassium channel activation properties.It is generally used in clinical practice to treat angina pectoris and provides long-term cardioprotection.On the one hand,nicorandil has nitric acid group,which can produce nitric oxide,activate guanylate cyclase,dilate vascular smooth muscle,and reduce cardiac load;on the other hand,it can also open the ATP sensitive potassium channel on the mitochondrial membrane,reduce calcium overload,and protect cells.KATP channels are widely distributed in brain tissue,and their opening agents have important brain protective effects,which can affect many neurological diseases such as epilepsy,Alzheimer’s disease,etc.At present,the effect of nicorandil as an ATP sensitive potassium channel opening agent on epileptic behavior has not been reported,so this was explored in this experiment.Part 1 Effect of nicorandil on acute epilepsy model MES,MMS, and PTZ chronic epilepsy modelsObjective: To observe the role of nicorandil in the induced epilepsy model of acute and chronic PTZ.Methods: 1.Establish an MES model and observe its effect on candor by intraperitoneal injection of model mice.2.The MMS model was established to observe its effect on the seizure rate and incubation time of mice by intraperitoneal injection.3.Establish a PTZ chronic epilepsy model,and locally give nicorandil during the molding process to observe its effect on the mortality,seizure grade and incubation time of mice.Results: In the MES model,the maximum electroconvulsive protection rate increased significantly in the nicorandil group compared with the control group(*P<0.05,* * P<0.01).As seen from the dose-effect curve,the antiepileptic effect of nicorandil in the MES model was dose-dependent,and its ED50=2.18mg/kg.In the MMS model,the protection rate of control mice was 25% and1,3,5 mg / kg of nicorandil were 25%,50%,and 45%,respectively.Latency time of seizures in each group showed that control was 10.8 ± 1.3 min,1mg /kg nicorandil group was 16.8 ± 1.2 min,3mg / kg nicorandil group was 23.9 ±1.5 min and 5mg / kg nicorandil group was 22.9 ± 1.5 min.By statistical analysis,the mice were significantly different between the nicorandil group and the control group(*P<0.05,* *P<0.01,* * * P<0.001).In a PTZ chronic epilepsy model,the onset of seizures after PTZ administration caused slow weight growth in mice,while administration of nicorandil ameliorated the phenomenon of slow weight growth induced by PTZ.The grade of epileptic seizures in each group was assessed,and compared to the PTZ + Vehicle group,the grade was significantly lower in both the PTZ + Nicorandil 1 mg / kg and PTZ + Nicorandil 3 mg / kg groups(*P<0.05).Five mice in the PTZ + Vehicle group died,with a 50% mortality;three mice in the PTZ + Nicorandil 1 mg / kg group with a 30% mortality;two mice in the PTZ + Nicorandil 3 mg / kg group died,with a 20% mortality;mice in the Control + Vehicle group did not have seizures or death.In the results of the minimal clonic seizure latency(MCS),the MCS for the PTZ +Vehicle,PTZ + Nicorandil 1 mg / kg,and PTZ + Nicorandil 3 mg / kg groups were 68±15s,117 ± 11 s,and 154 +±20s,respectively.Compared to PTZ+Vehicle,MCS was longer in PTZ + Nicorandil(* * *P<0.001),and there were significant differences between the Nicorandil 1 mg / kg and Nicorandil3 mg / kg groups(# P<0.05).In the results of generalized tonic-clonic seizure latency(GTCS),GTCS was 57 TZ + 9s,148 ±+13s,and 191±20s for PTZ+Nicorandil 1mg/kg and PTZ + Nicorandil 3 mg / kg,respectively.Compared to PTZ + Vehicle,GTCS was longer in PTZ + Nicorandil(* * *P<0.001),and there were significant differences between the Nicorandil 1 mg / kg and Nicorandil 3 mg / kg groups(#P<0.05).Conclusions: In the MES and MMS models,intraperitoneal injection of nicorandil had a better antiepileptic effect.In the PTZ chronic epilepsy model,local injection of nicrodidil in the hippocampus also had a better antiepileptic effect.Part 2 Alterations in the excitability of pyramidal neurons in the CA1 region of the hippocampus in an acute and chronic epilepsy model.Objective: To prepare models of acute and chronic PTZ-induced epilepsy and observe the altered excitability of pyramidal neurons in the CA1 region of the hippocampus of the model mice.Methods: A mouse model of acute and chronic PTZ induced epilepsy were established;hippocampus brain slices were prepared and the pyramidal neuron firing in the CA1 hippocampus was recorded using loose attach patch clamp recording.Results: The firing of pyramidal neurons in the CA1 region of the hippocampus was much higher in the acute PTZ induced seizure group than that in the control group,whose firing frequency was 2.08±0.32 Hz,while the acute PTZ induced seizure firing frequency increased to 8±0.34 Hz,showing a significant difference.Moreover,the ISI peak was shifted significantly to the left in the PTZ group compared to controls,with a significant increase in burst spikes from none to 39%.The firing rate of chronic PTZ induced seizures was also much higher than that of the control group,where the discharge frequency was 2.555±0.205 Hz,while the discharge frequency of chronic PTZ induced seizures was increased to 28.629±5.894 Hz,which was significantly different.Moreover,the ISI peak was significantly shifted to the left,with a significant increase in burst spikes from none to 76%.Conclusions: In either acute or chronic PTZ-induced seizures,the excitability of pyramidal neurons in the CA1 area of mouse hippocampus was increased,and burst firing also increased significantly.Part 3 Mechanism of antiepileptic action of nicorandilObjective: To test the effect of nicorandil on excitability of pyramidal neurons in the CA1 region of epileptic mice.Methods: A mouse model of acute and chronic PTZ induced epilepsy were established;hippocampus brain slices were prepared and the pyramidal neuron firing in the CA1 hippocampus was recorded using loose attach patch clamp recording,nicorandil infusion was used to observe changes in neuronal excitability.Results: The firing frequency of the acute PTZ epilepsy group was7.64±0.78 Hz,while the firing frequency of nicorandil decreased to1.424±0.530 Hz.Furthermore,the ISI peak was significantly shifted to the right in the nicorandil group compared to the PTZ group,and the burst spikes decreased from 47% to 22%,which was significantly reduced.The firing frequency in the chronic PTZ epilepsy group was 23.885±5.125 Hz,while the nicorandil group was decreased to 11.627±4.747 Hz,with a significant reduction.Moreover,the peak ISI was significantly shifted to the right with a significant decrease in the burst spikes from 77% to 45% compared to the chronic PTZ group.Conclusions: Nicorandil reversed the increase in firing frequency and burst spikes caused by PTZ.Local injection of nicorandil in the hippocampus suppressed the chronic PTZ induced increase in excitability and burst firing of pyramidal neurons in the CA1 hippocampus.Part 4 Clinical characteristics analysis of epilepsy patients with cognitive,emotional,and personality disorders.Objective:Evaluate the cognitive function,emotional state,and personality characteristics of adult idiopathic epilepsy patients and explore whether there is a correlation between clinical features of epilepsy and cognitive function.Methods: The cognitive function of epilepsy patients was assessed by Montreal cognitive assessment(Mo CA),the mental state was assessed by Hamilton depression scale(HAMD),and the personality characteristics were assessed by Eysenck Personality Questionnaire(revised version in China).Study the influence of different types of epilepsy on cognitive function,the degree of different types of epilepsy depression and personality characteristics analysis,the influence of epilepsy related factors on cognitive function and the correlation between depression,personality characteristics and cognitive function.Results: The generalized epilepsy group performed worse than the control group on tests of cognitive function except orientation,and the focal epilepsy group performed worse on memory,language,and visuospatial/executive function.The HAMD scale scores were higher in the generalized epilepsy and focal epilepsy groups than in the control group.The Eysenck personality questionnaire scores on neuroticism and dissembility scale were higher than those of control group.Among Mo CA’s subprojects are memory,language,visual-spatial/executive function,naming,attention,orientation,and abstract thinking.Memory function was significantly correlated with age of onset of epilepsy,course of disease and frequency of epilepsy(P<0.05).Language function was significantly correlated with age of onset,course of disease and frequency of epilepsy(P<0.05).Visual space/executive function was significantly correlated with age of onset of epilepsy,course of disease and frequency of epilepsy(P<0.05).The naming was significantly correlated with age of onset of epilepsy,course of disease and frequency of epilepsy(P<0.05).Attention was significantly correlated with age of onset,duration of epilepsy,history of epileptic status and frequency of epilepsy(P<0.05).Orientation was significantly correlated with age of onset,duration of epilepsy,history of epileptic status and frequency of epilepsy(P<0.05).Abstract thinking was significantly correlated with age of onset of epilepsy,course of disease and frequency of epilepsy(P<0.05).There was no significant correlation between HAMD scale and Mo CA scale in epilepsy group.There was significant correlation between psychotic personality and memory function in Eysenck personality questionnaire(P<0.05).Conclusions: Cognitive impairment may be associated with epilepsy.The cognitive impairment of idiopathic epilepsy was significantly correlated with the age of onset of epilepsy,the course of the disease,the history of epileptic status,and the frequency of seizures.People with idiopathic epilepsy are more prone to depressive tendencies and personality changes. |
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