Rate of quantal transmitter release at the mammalian rod synapse.
Rate of quantal transmitter release at the mammalian rod synapse.
复制标题
哺乳动物杆状突触的量子递质释放率。
DOI：
10.1016/s0006-3495(94)80454-0
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发表时间：
1994
影响因子：
3.4
通讯作者：
Sterling,P
中科院分区：
文献类型：
--
作者：
Rao,R;Buchsbaum,G;Sterling,P
在暗视条件下，哺乳动物的杆在其积分时间内编码一个光子或不编码一个光子。因此，提供给突触末端的信号是二进制的。突触有一个单一的活性区，在黑暗中量子释放神经递质，并短暂暂停以响应光子的视紫红质异构化。我们问：什么最小的紧张率可以让突触后双极细胞区分这种暂停和由于随机释放时间而导致的量子之间的超长间隔？答案需要一个电路模型，其中包括会聚到双极电池上的杆以及双极电池的信噪比。模型计算表明，强直释放必须至少为 40 量子/秒。这种强直率比传统突触高得多，传统突触的可靠性是通过采用多个活动区来实现的。视杆的突触机制可以有效利用空间，这在视网膜中是非常宝贵的。
Under scotopic conditions, the mammalian rod encodes either one photon or none within its integration time. Consequently the signal presented to its synaptic terminal is binary. The synapse has a single active zone that releases neurotransmitter quanta tonically in darkness and pauses briefly in response to a rhodopsin isomerization by a photon. We asked: what minimum tonic rate would allow the postsynaptic bipolar cell to distinguish this pause from an extra-long interval between quanta due to the stochastic timing of release? The answer required a model of the circuit that included the rod convergence onto the bipolar cell and the bipolar cell's signal-to-noise ratio. Calculations from the model suggest that tonic release must be at least 40 quanta/s. This tonic rate is much higher than at conventional synapses where reliability is achieved by employing multiple active zones. The rod's synaptic mechanism makes efficient use of space, which in the retina is at a premium.