[italic]In Vitro[/italic] Study the Mechanisms of Antiepileptic Drugs on Experimental Epilepsy.
Abstract number :
3.041
Submission category :
Year :
2001
Submission ID :
164
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
H. Zhang, Ph.D.,M.D., Dept. of Psychology, University of Michigan, Ann Arbor, MI; Y. Hu, Ph.D., Dept. of Radiation Oncology, University of Michigan, Ann Arbor, MI; S. He, Ph.D., Dept. of Biochemistry, Tongji Medical University, Wuhan, Hubei, China
RATIONALE: Phenytoin(PHT) and valproic acid(VPA)have been used to treat epilepsy for a long time in clinic.But the antiepileptic mechanisms of these drugs are not clear.This article is aim at using kindled cerebral cortex neurons to study the antiepileptic mechanisms of these drugs.
METHODS: [gamma]-aminobutyric acid transaminase(GABA-T);calcium; glutamate(Glu),[gamma]-aminobutyric acid(GABA), glycine(Gly),aspartate(Asp) in kindled neurons from neonatal Sprague-Dawley rats were measured by microultraviolet spectrophotometry,fluorometry and high performance liquid chromatography.Cell protein was detected by Lowry[ssquote]s method.
RESULTS: First,PHT increase intracellular Asp(20.53[plusminus]3.39 nmol/mgpr,control is 15.46[plusminus]3.83nmol/mgpr,n=6 the same below) and GABA(35.49[plusminus]11.15nmol/mgpr,control is 19.92[plusminus]5.08nmol/mgpr),and do not affect the levels of Glu(32.83[plusminus]5.04nmol/mgpr,control is 32.22[plusminus]5.66nmol/mgpr) and Gly(42.45[plusminus]7.29 nmol/mgpr,control is 42.96[plusminus]12.54nmol/mgpr) in kindled neurons.VAP decreased intracellular Asp (10.94[plusminus]2.20nmol/mgpr) and Gly(21.05[plusminus]10.54 nmol/mgpr),and do not influence the levels of Glu(31.06[plusminus]6.57 nmol/mgpr) and GABA(18.41[plusminus]4.07 nmol/mgpr) in kindled neurons.Both PHT and VPA decrease the extracellular Glu(32.53[plusminus]8.18nmol/mgpr, 32.33[plusminus]9.57 nmol/mgpr,control is 44.58[plusminus]13.62 nmol/mgpr) and Asp(9.45[plusminus]2.16nmol/mgpr, 9.56[plusminus]3.74nmol/mgpr,control is 15.57[plusminus]5.56 nmol/mgpr) in kindled neurons.Secondly,both PHT and VPA do not affect intracellular GABA-T(41.59[plusminus]6.07IU/mgpr, 38.60[plusminus]6.84IU/mgpr,control is 40.44[plusminus]6.37IU/mgpr) in kindled neurons.Thirdly,both PHT and VPA lower intracellular calcium(81.34[plusminus]5.67nmol/L,140[plusminus]18.67nmol/L) in kindled neurons;The level of calcium return to baseline (156.87[plusminus]9.64nmol/L,176.43[plusminus]8.97nmol/L) 5min later in PHT treated kindled neurons and never return to baseline 15min later in VPA treated neurons.
CONCLUSIONS: The antiepileptic mechanisms of two drugs may be:PHT increased production of intracellular GABA and calcium,and decreased production of extracellular Asp and Glu,and decreased secretion of Glu and Asp in kindled neurons.VPA dereased production of Asp and Gly and calcium,and secretion of Glu,Asp in kindled neurons.