海洛因急、慢性给药状态下大鼠海马CA1区生物电活动的记录

RECORDING BIO-ELECTRICAL ACTIVITY IN RAT HIPPOCAMPAL CA1 AREA UNDER A STATE OF ACUTE OR CHRONIC HEROIN ADMINISTRATION

目的:记录海洛因慢性给药戒断期大鼠离体海马脑片和海洛因急性灌流正常大鼠离体海马脑片生物电活动,观察其特征性变化。方法:制作海洛因慢性给药戒断大鼠模型及其海马离体脑片,正常组大鼠海马脑片用两种浓度海洛因急性灌流,分别记录海马CA1区神经元的电活动。结果:慢性给药戒断状态:大鼠海马CA1神经元的被动电学性质与各组比较差异无显著性,但锋电位的半幅时程、10%-90%衰减时间显著缩短(P<0.05,P<0.01);给予1.6-2.0nA胞内电流刺激时,放电频率较对照组增加(P<0.01);CA1区神经元兴奋性突触后电位(EPSP)幅值显著增强(P<0.01)。急性灌流用药:0.3mmol.L-1海洛因灌流,使膜电位和阈值绝对值减小(P<0.05,P<0.01),锋电位的半幅时程、10%-90%衰减时间显著延长(P<0.05,P<0.01);膜斜率电阻增大(P<0.01),EPSP幅值显著下降(P<0.01)。结论:海洛因急、慢性给药状态下,大鼠海马CA1区生物电特性存在着明显的差别。

Objective：Recording bio-electrical activity from isolated rat hippocampal slices at heroin withdrawal period after chronic heroin administration and normal rat hippocampal slices in vitro at heroin acute perfusion,to observe the characteristic changes.Methods：The isolated hippocampal slices from rat model at acute withdrawal following chronic heroin administration,or normal rat hippocampal slices using two different concentrations of heroin by direct reperfusion were prepared,respectively,and the electrical activity of neurons were recorded in hippocampal CA1 area.Results：At withdrawal state after chronic heroin administration：the passive electrical properties of rat hippocampal CA1 neurons showed no significant difference compared with the control,but the half-width duration and 10%-90% decaytime of action potential significantly shortened（P0.05,P0.01）;the average discharge frequency increased（P0.01）by 1.6-2.0 nA intracellular stimulus;the amplitude of excitatory postsynaptic potential（EPSP）in CA1 pyramidal neurons was reinforced significantly（P0.01）.At acute heroin administration：0.3 mmol·L-1 heroin by direct perfusion,the absolute values of membrane resting potential and threshold potential decreased（P0.05,P0.01）,the half-with duration and 10%-90% decaytime of action potential were elongated（P0.05,P0.01）;membrane slope resistance was enlarged（P0.01）,and the amplitude and the curve area of EPSP decreased significantly（P0.01）.Conclusion：The bio-electrical properties of hippocampus CA1 pyramidal neurons in two administration states present significant differences.