Pan Bin, Zucker Robert S
Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA.
Neuron. 2009 May 28;62(4):539-54. doi: 10.1016/j.neuron.2009.03.025.
Some synapses transmit strongly to action potentials (APs), but weaken with repeated activation; others transmit feebly at first, but strengthen with sustained activity. We measured synchronous and asynchronous transmitter release at "phasic" crayfish neuromuscular junctions (NMJs) showing depression and at facilitating "tonic" junctions, and define the kinetics of depression and facilitation. We offer a comprehensive model of presynaptic processes, encompassing mobilization of reserve vesicles, priming of docked vesicles, their association with Ca(2+) channels, and refractoriness of release sites, while accounting for data on presynaptic buffers governing Ca(2+) diffusion. Model simulations reproduce many experimentally defined aspects of transmission and plasticity at these synapses. Their similarity to vertebrate central synapses suggests that the model might be of general relevance to synaptic transmission.
一些突触能强烈地传递动作电位（APs），但会随着重复激活而减弱；另一些突触起初传递微弱，但会随着持续活动而增强。我们测量了呈现抑制作用的“相位性”小龙虾神经肌肉接头（NMJs）以及具有易化作用的“紧张性”接头处的同步和异步递质释放，并确定了抑制和易化的动力学。我们提供了一个突触前过程的综合模型，包括储备囊泡的动员、停靠囊泡的引发、它们与Ca(2+)通道的关联以及释放位点的不应性，同时考虑了关于控制Ca(2+)扩散的突触前缓冲的数据。模型模拟重现了这些突触传递和可塑性的许多实验定义方面。它们与脊椎动物中枢突触的相似性表明该模型可能与突触传递普遍相关。
