LoGiudice Lisamarie, Matthews Gary
Department of Neurobiology and Behavior, State University of New York, Stony Brook, New York 11794-5230, USA.
Neuroscientist. 2009 Aug;15(4):380-91. doi: 10.1177/1073858408331373. Epub 2009 Mar 4.
Synaptic ribbons are organelles that tether vesicles at the presynaptic active zones of sensory neurons in the visual, auditory, and vestibular systems. These neurons generate sustained, graded electrical signals in response to sensory stimuli, and fidelity of transmission therefore requires their synapses to release neurotransmitter continuously at high rates. It has long been thought that the ribbons at the active zones of sensory synapses accomplish this task by enhancing the size and accessibility of the readily releasable pool of synaptic vesicles, which may represent the vesicles attached to the ribbon. Recent evidence suggests that synaptic ribbons immobilize vesicles in the resting cell and coordinate the transient, synchronous release of vesicles in response to stimulation, but it is not yet clear how the ribbon can efficiently mobilize and coordinate multiple vesicles for release. However, detailed anatomical, electrophysiological, and optical studies have begun to reveal the mechanics of release at ribbon synapses, and this multidisciplinary approach promises to reconcile structure, function, and mechanism at these important sensory synapses.
突触带是一种细胞器，它将囊泡拴系在视觉、听觉和前庭系统中感觉神经元的突触前活动区。这些神经元在受到感觉刺激时会产生持续的、分级的电信号，因此，为保证传递的保真度，其突触需要以高速率持续释放神经递质。长期以来，人们一直认为，感觉突触活动区的突触带通过增加突触囊泡易释放池的大小和可及性来完成这项任务，易释放池可能是指附着在突触带上的囊泡。最近的证据表明，突触带在静息细胞中将囊泡固定，并在受到刺激时协调囊泡的瞬时同步释放，但目前尚不清楚突触带如何有效地动员和协调多个囊泡进行释放。然而，详细的解剖学、电生理学和光学研究已经开始揭示突触带突触的释放机制，这种多学科方法有望在这些重要的感觉突触上协调结构、功能和机制。
