Huang E P, Stevens C F
Neuroscience Department, University of California San Diego, La Jolla 92093, USA.
J Neurophysiol. 1997 Dec;78(6):2870-80. doi: 10.1152/jn.1997.78.6.2870.
Using whole cell recording from CA1 hippocampal pyramidal neurons in slices, we examined the progressive decrease of N-methyl-D-aspartate receptor-mediated synaptic responses in the presence of the open-channel blocker MK-801. Previous studies analyzing this decrease have proposed that hippocampal synapses fall into two distinct classes of release probabilities, whereas studies based on other methods indicate a broad distribution of synaptic reliabilities exists. Here we derive the theoretical relationship between the MK-801-mediated decrease in excitatory postsynaptic current amplitudes and the underlying distribution of synaptic reliabilities. We find that the MK-801 data are consistent with a continuous distribution of synaptic reliabilities, in agreement with studies examining individual synapses. In addition, changes in the MK-801-mediated decrease in response size as a consequence of altering release probability are consistent with this continuous distribution of synaptic reliabilities.
利用脑片上CA1海马锥体神经元的全细胞记录，我们研究了在开放通道阻断剂MK - 801存在的情况下，N - 甲基 - D - 天冬氨酸受体介导的突触反应的逐渐降低。此前分析这种降低现象的研究提出，海马突触可分为两类不同释放概率的类型，而基于其他方法的研究表明存在广泛的突触可靠性分布。在这里，我们推导了MK - 801介导的兴奋性突触后电流幅度降低与潜在突触可靠性分布之间的理论关系。我们发现，MK - 801数据与突触可靠性的连续分布一致，这与研究单个突触的结果相符。此外，由于释放概率改变导致的MK - 801介导的反应大小降低的变化，也与这种突触可靠性的连续分布一致。
