Szapiro Germán, Barbour Boris
Laboratoire de Neurobiologie, Ecole Normale Supérieure, CNRS, 46 rue d'Ulm, 75005 Paris, France.
Nat Neurosci. 2007 Jun;10(6):735-42. doi: 10.1038/nn1907. Epub 2007 May 21.
Spillover of glutamate under physiological conditions has only been established as an adjunct to conventional synaptic transmission. Here we describe a pure spillover connection between the climbing fiber and molecular layer interneurons in the rat cerebellar cortex. We show that, instead of acting via conventional synapses, multiple climbing fibers activate AMPA- and NMDA-type glutamate receptors on interneurons exclusively via spillover. Spillover from the climbing fiber represents a form of glutamatergic volume transmission that could be triggered in a regionalized manner by experimentally observed synchronous climbing fiber activity. Climbing fibers are known to direct parallel fiber synaptic plasticity in interneurons, so one function of this spillover is likely to involve controlling synaptic plasticity.
在生理条件下，谷氨酸溢出仅被确认为传统突触传递的辅助方式。在此，我们描述了大鼠小脑皮质中攀缘纤维与分子层中间神经元之间一种纯粹的溢出连接。我们发现，多条攀缘纤维并非通过传统突触起作用，而是仅通过溢出作用激活中间神经元上的AMPA型和NMDA型谷氨酸受体。攀缘纤维的溢出代表了一种谷氨酸能容积传递形式，可通过实验观察到的同步攀缘纤维活动以区域化方式触发。已知攀缘纤维可指导中间神经元中平行纤维的突触可塑性，因此这种溢出的一个功能可能涉及控制突触可塑性。
