Low W C, BeMent S L, Whitehorn D
Exp Neurol. 1983 Apr;80(1):9-22. doi: 10.1016/0014-4886(83)90002-x.
The mechanisms of paired-pulse potentiation of the CA1 pyramidal cell population were examined by determining input-output relations for control and potentiated responses originating from the activation of radiatum fibers in the hippocampal slice preparation. Two types of potentiation for synchronously discharging pyramidal cells (population spike) were observed. In the first type, the potentiation of the population spike was found to be a combination of synaptic and extrasynaptic factors. This form of potentiation was observed in 16 of 28 slices. In the second type, the potentiation of the population spike was attributed entirely to the potentiation of summated dendritic depolarizations (population EPSP). This synaptic process of potentiation was observed in 12 of 28 slices. The involvement of only extrasynaptic mechanisms in the paired-pulse potentiation of the population spike was not observed. For the potentiation originating from a combination of synaptic and extrasynaptic mechanisms, 60% of the potentiation of the population spike was a result of synaptic factors and 40% could be attributed to extrasynaptic factors. These results support the concept that alterations in the excitability of postsynaptic neurons serve as a component of the mechanisms of paired-pulse potentiation in the radiatum fiber-CA1 pyramidal cell system.
通过确定源自海马切片制备中辐射层纤维激活的对照反应和增强反应的输入-输出关系，研究了CA1锥体细胞群体配对脉冲增强的机制。观察到同步放电的锥体细胞（群体峰电位）存在两种类型的增强。在第一种类型中，群体峰电位的增强被发现是突触和突触外因素的组合。在28个切片中的16个中观察到这种增强形式。在第二种类型中，群体峰电位的增强完全归因于总和树突去极化（群体兴奋性突触后电位）的增强。在28个切片中的12个中观察到这种突触增强过程。未观察到仅突触外机制参与群体峰电位的配对脉冲增强。对于源自突触和突触外机制组合的增强，群体峰电位增强的60%是突触因素的结果，40%可归因于突触外因素。这些结果支持这样的概念，即突触后神经元兴奋性的改变是辐射层纤维-CA1锥体细胞系统中配对脉冲增强机制的一个组成部分。
