Harris E W, Cotman C W
Exp Brain Res. 1983;52(3):455-60. doi: 10.1007/BF00238039.
The glutamate analogue 2-amino-4-phosphonobutyric acid (APB) has been shown to selectively reduce synaptic transmission along the lateral portion of the perforant path input to the dentate gyrus. APB is studied here with respect to effects on paired-pulse potentiation (PPP) along the perforant path. Application of APB causes a reduction in lateral perforant path responses, but also an increase in the %PPP of that response. The effect does not result simply from reducing response size, because the amount of potentiation of matched first responses increases, and also because APB reduces the potentiated response proportionately less than a comparable first response. A similar effect is seen by decreasing extracellular calcium. Reducing lateral perforant path responses with kynurenic acid, which apparently acts on postsynaptic sites, does not have a similar effect on PPP. These results may indicate a presynaptic action of APB, possibly mediated via an effect on presynaptic calcium availability.
谷氨酸类似物2-氨基-4-膦酰丁酸（APB）已被证明可选择性地减少沿穿通通路输入齿状回的外侧部分的突触传递。本文研究了APB对沿穿通通路的双脉冲增强（PPP）的影响。应用APB会导致外侧穿通通路反应减少，但该反应的PPP百分比也会增加。这种效应并非仅仅源于反应大小的减小，因为匹配的第一个反应的增强量增加，而且还因为APB使增强反应的减少比例小于可比的第一个反应。通过降低细胞外钙也可以看到类似的效果。用犬尿氨酸减少外侧穿通通路反应，犬尿氨酸显然作用于突触后位点，但对PPP没有类似的影响。这些结果可能表明APB的突触前作用，可能是通过对突触前钙可用性的影响介导的。
