Woodson P B, Schlapfer W T, Tremblay J P, Barondes S H
Brain Res. 1976 Jun 4;109(1):41-59. doi: 10.1016/0006-8993(76)90379-6.
When a pair of stimuli separated by an appropriate interval is given to the right visceropleural connective of Aplysia californica the amplitude of the second EPSP elicited in cell R15 is usually smaller than the amplitude of the first EPSP. In the present paper we show that this phenomenon, synaptic depression, can be analyzed in terms of the material flow model of neurotransmitter economics developed in our preceding publications. We specifically show how changes in the 4 model parameters; A, the available pool of transmitter; F, the fraction of the available pool released by a presynaptic action potential; M, the rate of transmitter mobilization into the available pool; and D, the rate constant of demobilization of transmitter from the available pool, all effect synaptic depression. In addition, we show how transient changes in F and M, that are observed immediately and for seconds after a stimulus, influence the time course of synaptic depression. Using this analysis we then tested our previous inferences about changes in the model parameters produced either by pharmacological manipulations or repetitive stimulation, by comparing the observed effects of these manipulations on synaptic depression with the theoretical predictions. The theoretical and experimental findings agreed, thereby strengthening both our previous conclusions of the mode of action of these manipulations and the model itself.
当以适当的间隔给加州海兔的右侧内脏胸膜结缔组织施加一对刺激时，在R15细胞中引发的第二个兴奋性突触后电位（EPSP）的幅度通常小于第一个EPSP的幅度。在本文中，我们表明这种现象，即突触抑制，可以根据我们之前发表的神经递质经济学的物质流模型来进行分析。我们具体展示了4个模型参数的变化；A，递质的可用库；F，由突触前动作电位释放的可用库的比例；M，递质动员到可用库中的速率；以及D，递质从可用库中解动员的速率常数，如何都对突触抑制产生影响。此外，我们展示了在刺激后立即以及数秒内观察到的F和M的瞬态变化如何影响突触抑制的时间进程。利用这种分析，我们通过比较这些操作对突触抑制的观察效果与理论预测，检验了我们之前关于由药理学操作或重复刺激引起的模型参数变化的推断。理论和实验结果一致，从而加强了我们之前关于这些操作作用方式的结论以及模型本身。
