Effect And Mechanism Of Jingzhaotoxin-V(JZ-V)on Synaptic Plasticity In Rat Hippocampal

Object：To research further on the nootropic action of JZ-V and analyse themechanism of its nootropic action tentatively based on the preliminary experimentalresults.Method: The extracellular recordings techniques in vivo were used to investigate theeffect of3nM and30nM JZ-V injected by lateral ventricle in vivo on LTPmaintenance from PP-DG of anesthetized rats; Using hippocampal slice preparationsand the extracellular recordings techniques in vitro, we investigated the effects ofJZ-V on basal synaptic transmission, induction and maintenance of LTP in theSchaffer Collateral-CA1region of rat hippocampal slices; A method of implantingcannula into the lateral ventricle of the rat was used to injecting JZ-V into the lateralventricle continuously on7days, and then, dissecting the cortex and hippocampalfrom the removed brains. Using western blot technique to analyzed the expression ofp38MAPK, phospho-p38MAPK, CREB and phospho-CREB.Results:1. Neither of3nM and30nM JZ-V had significant effect on the maintenance ofLTP in the dentate gyrus region of anesthetized rats.2. JZ-V did not affect basal synaptic transmission in the Schaffer Collateral-CA1region of rat hippocampal slices both at3nM and30nM; Both the two concentrationJZ-V did enhance the induction of LTP in the Schaffer Collateral-CA1region of rathippocampal slices, but the two enhancement have no significant variation; Neitherthe3nM nor the30nM of JZ-V did have significant effect on the maintenance of LTPin the Schaffer Collateral-CA1region of rat hippocampal slices.3. The expression of phospho-p38MAPK and phospho-CREB were significantly enhanced in the cortex and hippocampal compared with the control group(P＜0.01);the expression of p38MAPK and CREB had no significant variation in the cortex andhippocampal compared with the control group.Conclusion:1. JZ-V had no significant effect on the maintenance of LTP in the dentate gyrusregion of anesthetized rats.2. JZ-V enhanced the induction of LTP in the Schaffer Collateral-CA1region ofrat hippocampal slices, had no significant effect on basal synaptic transmission andthe maintenance of LTP.3. p38MAPK/CREB signaling pathway may be one of the targets on nootropicaction of JZ-V.