慢性铅暴露对在体诱导年轻大鼠海马齿状回LTP的损害作用  

CHRONIO LEAD EXPOSURE IMPAIRS IN VIVO INDUOTION OF LONGTERM POTENTIATION IN YOUNG RAT HIPPOCAMPAL DENTATE GYRUS

作　　者：时利德[1] 蔡葵[1] 滕国玺[1] 万伯健[1] 孙黎光[1] 

机构地区：[1]中国医科大学神经生理研究室

出　　处：《中国应用生理学杂志》1998年第1期82-86,共5页Chinese Journal of Applied Physiology

基　　金：国家自然科学基金

摘　　要：本文研究了慢性铅暴露对大鼠在体诱导海马ＬＴＰ的影响。对照组和实验组动物从断乳至测试止，分别饮用蒸馏水和０．２％醋酸铅溶滚。应用细胞外微电极记录单脉冲刺激穿通路纤维在海马齿状回诱发的群体锋电位（ＰＳ），测量高频刺激（ＨＦＳ）前后单脉冲刺激诱发的ＰＳ的幅值及其变化，并进行组间比较。ＨＦＳ前的基线记录显示，两组间ＰＳ的平均幅值及峰潜伏期的差异无显著意义；ＨＦＳ后，１２只对照鼠有１０只产生了ＬＴＰ，其ＰＳ平均幅值增加，为基线值的１４２．７％；１１只染铅鼠只有２只产生了ＬＴＰ，其平均幅值为基线值的１２０％，但却有７只鼠产生了ＬＴＤ，其ＰＳ平均幅值低于基线值，仅为基线值的７０％。结果表明，慢性铅暴露（血铅浓度９９．２μｇ／１００ｍｌ）可使在体海马齿状回ＬＴＰ发生率和ＬＴＰ增幅明显降低，甚至在部分动物以ＬＴＤ代替了ＬＴＰ。提示慢性铅暴露可损害ＬＴＰ的诱导和维持。? The effects of chronic lead exposure on longterm potentiaion(LTP) induced in young rat hippocampal dentate were investigated.Control and exposed groups of male wistar rat were fed distilled water and 0. 2%pbacetate, respectively, for whole periol from weaning until electrophysiological testing.Population spike (PS)　were　recorded　in　the　dentate　gyrus　in　response　to　single　pulse　stimulation　applied　to　perforant　path(PP)　with　extracelluar　microelectrode　technique.The　PS　baseline　recordings　evoked　by　single　pulse　revealed　no　difference　between　the　two　groups　with　respect　to　the　man　PS　amplitude　and　peak.latency　before　highfrequency　stimulation(HFS)(P>0.1,P>0.5　respectively).　After　the　application　of　the　HFS,LTP　was　induced　in　10　of　12　control　rats　with　a　mean　increase　in　relation　to　baseline　amplitude　to　142.7%±15.1%　(n=10,range:125%-170%),only　two　of　eleve　Pbexposed　rats　showed　a　small　smount　of　LTP　with　a　mean　increase　to　only　120.1%±7.1%(n=2,range:113%-127.3%).However,seven　of　eleven　Pbexposed　rats　showed　longterm　depresson(LTD)　with　a　mean　decrease　ralative　to　the　baseline　values　to　70%±4.35%(n=7,range:65%-75%)　after　HFS.These　finding　showed　that　the　incidence　of　LTP　induction　declined　and　amplitude　of　LTP　decreased　markedly,even　a　large　porportion　of　Pb-exposed　rats　expressed　LTD　instead　of　LTP　following　chronic　lead　exposure.The　sesults　suggest　that　chronic　lead　exposure　may　impair　the　induction　and　maintenace　of　LTP　in　vivo.

关 键 词：慢性 长时程增强 海马 齿状回 铅中毒 

分 类 号：R992[医药卫生—毒理学] R995[医药卫生—药学]