A computational study of the role of spike broadening in synaptic facilitation of Hermissenda.
A computational study of the role of spike broadening in synaptic facilitation of Hermissenda.
复制标题
尖峰加宽在 Hermissenda 突触促进中的作用的计算研究。
DOI：
10.1023/a:1024418701765
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发表时间：
2003
影响因子：
1.2
通讯作者：
Crow,Terry
中科院分区：
文献类型：
--
作者：
Flynn,Mark;Cai,Yidao;Baxter,DouglasA;Crow,Terry
Hermissenda 中的巴甫洛夫调节导致电压依赖性（IK、A 和 ICa）和 Ca2+ 依赖性（IK、Ca）电流减少，并增加 B 型光感受器的动作电位 (AP) 持续时间。此外，B 和 A 光感受器以及 B 光感受器和 I 型中间神经元之间的突触连接也得到促进。通过减少一个或多个 K+ 电流而产生的 AP 持续时间的增加可能是突触促进的原因。本研究通过使用 B 光感受器和神经模拟器 SNNAP 的数学模型来研究这个问题。在该模型中，将 gK,A 降低 70%，使终末 AP 持续时间增加 41%，Ca2+ 流入增加 30%。然而，如果 gK,A 的减少与 gCa 的减少相结合，与实验报告类似，Ca2+ 流入量减少 54%。因此，ICa 的伴随变化抵消了突触末端加宽引起的 Ca2+ 流入的增加。这一结果表明，与尖峰持续时间无关的过程必定有助于巴甫洛夫条件反射后观察到的突触促进。
Pavlovian conditioning inHermissendaproduces a decrease in voltage-dependent (IK,Aand ICa) and Ca2+-dependent (IK,Ca) currents, and an increase in the action potential (AP) duration in type B-photoreceptors. In addition, synaptic connections between B and A photoreceptors and B photoreceptor and type I interneurons are facilitated. The increase in AP duration, produced by decreasing one or more K+currents, may account for synaptic facilitation. The present study examined this issue by using a mathematical model of the B-photoreceptor and the neurosimulator SNNAP. In the model, decreasing gK,Aby 70% increased the duration of the AP in the terminal by 41% and Ca2+influx by 30%. However, if the decrease in gK,Awas combined with a decrease in gCa, similar to what has been reported experimentally, the Ca2+influxdecreasedby 54%. Therefore, the concomitant change in ICacounter-acted the broadening-induced increase in Ca2+influx in the synaptic terminal. This result suggests that a spike-duration independent process must contribute to the synaptic facilitation observed following Pavlovian conditioning.