Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA.
Nat Neurosci. 2011 Jul 24;14(9):1135-41. doi: 10.1038/nn.2870.
In vision, balance and hearing, sensory receptor cells translate sensory stimuli into electrical signals whose amplitude is graded with stimulus intensity. The output synapses of these sensory neurons must provide fast signaling to follow rapidly changing stimuli while also transmitting graded information covering a wide range of stimulus intensity and must be able to sustain this signaling for long time periods. To meet these demands, specialized machinery for transmitter release, the synaptic ribbon, has evolved at the synaptic outputs of these neurons. We found that acute disruption of synaptic ribbons by photodamage to the ribbon markedly reduced both sustained and transient components of neurotransmitter release in mouse bipolar cells and salamander cones without affecting the ultrastructure of the ribbon or its ability to localize synaptic vesicles to the active zone. Our results indicate that ribbons mediate both slow and fast signaling at sensory synapses and support an additional role for the synaptic ribbon in priming vesicles for exocytosis at active zones.
在视觉、平衡和听觉中，感觉受体细胞将感觉刺激转化为电信号，其幅度随刺激强度而分级。这些感觉神经元的输出突触必须提供快速信号，以跟随快速变化的刺激，同时也传递涵盖广泛刺激强度范围的分级信息，并且必须能够长时间维持这种信号传递。为了满足这些需求，在这些神经元的突触输出处已经进化出了用于递质释放的特殊机制，即突触带。我们发现，用光破坏带状结构对小鼠双极细胞和蝾螈锥体的神经递质释放的持续和瞬态成分都有明显的破坏作用，而不会影响带状结构的超微结构或其将突触小泡定位到活性区的能力。我们的结果表明，带状结构介导感觉突触的慢和快信号传递，并支持突触带在为活性区的胞吐作用预先填充囊泡方面的额外作用。
