GABA能递质系统对P3a波的作用及其机制的研究

An experimental study of GABAergic effects on rabbit P3a potential and its mechanisms

目的 探讨扣带回及额叶等脑区GABA -A受体 (GABAAR)在P3a波产生中的作用及其相应机制。方法 记录和分析正常状态 (Normal)下以及分别在扣带前回前区 (AcgI)、扣带前回后区 (AcgII)、扣带后回 (Pcg)及背外侧额叶F3(F4 )依次微量注入生理盐水、不同浓度GABAAR拮抗剂Bicuculline及GABA后的ERPs。结果 Bicuculline在AcgI、AcgII、Pcg及F3(F4 )等区对P3a波具有显著不同的作用。但只在AcgI区Bicuculline除使P3a波潜伏期显著延长、波幅降低外 (P <0 .0 1) ,甚至可使P3a波消失 ,外源性GABA使P3a波复现。结论 AcgI区GABAAR的活动与P3a波的产生直接相关。GABAAR介导的IPSP可能是产生P3a波神经化学机制之一。AcgI区GABAAR的活动参与形成P3a波偶极子电穴和 或电源。

Objective To observe the effects of GABAAR in different brain areas on rabbit P3a and their mechanisms. MethodsWith sequential microinfusion of Bicuculline (a selective antagonist to GABAAR) into the Acg I,Acg II,F 3(F 4) and Pcg areas, P3a was recorded and analyzed, respectively. ResultsThere were different effects of Bicuculline on these brain areas, the P3a latency was markedly prolonged and/or amplitude was decreased following the infusion of Bicuculline with a dose dependent manner in the Acg I,F 3(F 4),Pcg, and P3a might even disappear in Acg I area. The effects of Bicuculline on the P3a could be reversed with microinfusion of GABA,but the P3a was not markedly affected by Bicuculline in Acg II. ConclusionThe GABAAR in the area of Acg I is involved in the generation of the P3a; the IPSP induced by GABAAR in Acg I is probably the main neurochemical basis for the generation of the P3a potential.