Kairiss E W, Abraham W C, Bilkey D K, Goddard G V
Brain Res. 1987 Jan 13;401(1):87-94. doi: 10.1016/0006-8993(87)91167-x.
Trains of high-frequency stimulation to the perforant path cause (i) long-term potentiation (LTP) of the population excitatory post-synaptic potential (EPSP), (ii) a lasting increase in the population spike, and (iii) a lasting alteration of the relationship between the EPSP and population spike (E-S relationship), consisting of a decreased x-intercept and decreased slope of the linear regression. To compare the thresholds of these changes, we applied a series of trains, increasing in duration from below LTP threshold. The EPSP potentiated with about the same low threshold as the reduction in E-S slope, whereas the reduction in E-S x-intercept required longer trains. In the second experiment, LTP of the EPSP was reduced by concurrent high-frequency stimulation of the commissural input and a lasting reduction of the population spike height was observed. In a third experiment, picrotoxin, an antagonist of gamma-aminobutyric acid (GABA)-mediated inhibition, blocked the decrease in slope of the E-S relationship which normally accompanies LTP. These results imply that perforant path/granule cell LTP is normally accompanied by long-term potentiation of a feed-forward inhibitory pathway which may involve interneurones.
（i）群体兴奋性突触后电位（EPSP）的长时程增强（LTP）；（ii）群体峰电位持续增加；（iii）EPSP与群体峰电位之间关系（E-S关系）的持续改变，表现为线性回归的x轴截距减小和斜率降低。为了比较这些变化的阈值，我们施加了一系列刺激序列，其持续时间从低于LTP阈值开始逐渐增加。EPSP增强的阈值与E-S斜率降低的阈值大致相同，而E-S x轴截距的降低则需要更长的刺激序列。在第二个实验中，通过同时对联合输入进行高频刺激，降低了EPSP的LTP，并观察到群体峰电位高度持续降低。在第三个实验中，γ-氨基丁酸（GABA）介导的抑制作用的拮抗剂苦味毒，阻断了通常伴随LTP出现的E-S关系斜率的降低。这些结果表明，穿通通路/颗粒细胞LTP通常伴随着前馈抑制通路的长时程增强，这可能涉及中间神经元。
