Study On Contents Of F-actin In Epilepsy Rat's Hippocampus Neuron And The Relation With Cell-cell Gap Junctional Communication

Objective:Microfilament is one component of cytoskeleton , and it is mainly composed of actin. Actin interacts with it' s binding protein, which have an important role in changing the dendritic spine' shape and in the plasticity of synapse . The morphology study of the epilepsia focus shows that the hippocampal neuron is necrosis or degeneration , the microfilament arrayed and tangled abnormally, the formation of the new synapse, the reduction of the dendrite and spine. Microfilament and it' s binding protein is the substructure of above-mentioned morphology change , which may have a indispensable role in the epileptogenesis. Meanwhile , the function of microfilament is regulated by the signal transducting system. The gap junction is the unique gap which can exchange material and information. It mediates cell-cell communication which is important in the accommodation of the microfilament. There is no report about the effect of epileptogenic matter and the gap junction on the expression of the microfilamentF-actin. Our objective is to understand the effect of the different epileptogenic matter as penicillin, coriaria lactone, bicuculline on the expression of hippocampus neuron microfilament F-actin and the relation with the gap junctional communication , and explore their significance in the epileptogenesis.Methods:We prepared primary neuron-rich cultures from hippocampus of postnatal 24h SD rats, the neuron is identified by the β Ⅲ -Tubulin. After five days, we change the culture medium to the medium without serum, and the cultured neurons were randomized into 5 gruoups as follows:(1)A group:control group (2)B group:epileptogenic matter (3) C group:epileptogenic matter+gap junctional Blocker (4)D group:epileptogenic matter + gap junctional Blocker+ carbamazepine (5)E group: epileptogenic matter + gap junctional Blocker+ Sodium valproate. After the above-mentioned treatment ,we incubate the cultured neuron for 48 hours. Then observe the structure and distribution of F-actin in neuron by immunofluorescence and laser scanning confocal microscope,measuring the relative fluorescent intensive of F-actin with the laserpix software.Results:We can find that the microfilament F-actin is well-distributed in the body, the axon and dendrite, there is no significant contrast with naked eye. After the effect of epileptogenic matter' s on the neuron of 48hours, the F-actin' s relative fluorescent intensive is lower than the control group (P<0. 05), whereas the F-actin' s relative fluorescent intensive ofthe C, D, E group is higher than the the control group (P<0. 01), and the increase of D, E groups' relative fluorescent intensive is more significant.ConclusionrEpileptogenic matter can decrease the content of the neuron' s F-actin. While the gap junctional blocker(1-hepatal), the antiepileptic drugs(sodium valproate, carbamazepine) can increase it when they exist together with the epileptogenic matter. These change of F-actin may affect the assembly of the neuron' s microfilament and the signal conduction between the neurons, it may have an important role in the origin of the epilepsy.