Efficiency of synaptic transmission of single-photon events from rod photoreceptor to rod bipolar dendrite.
Efficiency of synaptic transmission of single-photon events from rod photoreceptor to rod bipolar dendrite.
复制标题
从杆状光感受器到杆状双极树突的单光子事件的突触传递效率。
作者：
S. Schein;Kareem M. Ahmad
杆状物通过在杆状双极树突的积分期(约0.1S)内释放的少量神经递质量子(Q(计数))传输对单光子的吸收。由于释放的量子和随机性质，暗Q(计数)的离散分布与视紫红质(R*)的一个异构化的离散分布重叠。我们建议，释放必须是规则的，以缩小这些分布，减少重叠，降低假阳性率，并提高传输效率(识别为轻的R*事件的比例)。毫不奇怪，更高的量子释放率(Q(Rates))会产生更高的效率。这里着重于Q(速率)的微小变化的影响，我们发现，由于必须有固定的量子计数阈值，稍微较高的Q(速率)会导致效率大大降低。为了在Q(速率)漂移的情况下稳定效率，树枝晶需要调节其量子计数阈值相对于其Q(计数)的生化实现。这些考虑揭示了以钙为基础的负反馈的数学作用，并暗示了自发R*的有益作用。此外，为了使效率在面对漂移的规律性程度时保持稳定，效率应该在50%左右，类似于测量结果。
A rod transmits absorption of a single photon by what appears to be a small reduction in the small number of quanta of neurotransmitter (Q(count)) that it releases within the integration period ( approximately 0.1 s) of a rod bipolar dendrite. Due to the quantal and stochastic nature of release, discrete distributions of Q(count) for darkness versus one isomerization of rhodopsin (R*) overlap. We suggested that release must be regular to narrow these distributions, reduce overlap, reduce the rate of false positives, and increase transmission efficiency (the fraction of R* events that are identified as light). Unsurprisingly, higher quantal release rates (Q(rates)) yield higher efficiencies. Focusing here on the effect of small changes in Q(rate), we find that a slightly higher Q(rate) yields greatly reduced efficiency, due to a necessarily fixed quantal-count threshold. To stabilize efficiency in the face of drift in Q(rate), the dendrite needs to regulate the biochemical realization of its quantal-count threshold with respect to its Q(count). These considerations reveal the mathematical role of calcium-based negative feedback and suggest a helpful role for spontaneous R*. In addition, to stabilize efficiency in the face of drift in degree of regularity, efficiency should be approximately 50%, similar to measurements.
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影响因子：
56.9
作者：
SLAUGHTER, MM;MILLER, RF
通讯作者：
MILLER, RF
钙调神经磷酸酶对视网膜双极细胞 mGluR6 途径的调节。
影响因子：
2.5
作者：
Snellman,Josefin;Nawy,Scott
通讯作者：
Nawy,Scott
异步递质释放：控制蝾螈杆突触的胞吐作用和内吞作用。
DOI：
10.1113/jphysiol.1996.sp021360
发表时间：
1996
期刊：
The Journal of physiology
影响因子：
--
作者：
Rieke,F;Schwartz,EA
通讯作者：
Schwartz,EA
猕猴视网膜中视杆细胞和视锥细胞的光电压。
DOI：
10.1126/science.7754386
发表时间：
1995
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Schneeweis,DM;Schnapf,JL
通讯作者：
Schnapf,JL