Small conductance potassium channels cause an activity-dependent spike frequency adaptation and make the transfer function of neurons logarithmic
Small conductance potassium channels cause an activity-dependent spike frequency adaptation and make the transfer function of neurons logarithmic
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DOI：
10.1016/s0006-3495(99)77293-0
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发表时间：
1999-03-01
影响因子：
3.4
通讯作者：
Schild, D
中科院分区：
文献类型：
--
作者：
Engel, J;Schultens, HA;Schild, D
我们制作了单个神经元的计算模型，以研究小电导(SK)钙依赖的K+通道对棘波频率适应的影响。该模型神经元包括一个Na+电导、一个钙电导和两个不依赖于钙离子的K+电导，以及一个小的和大的(BK)钙激活的K+电导、一个钙泵以及钙的缓冲和扩散机制。模拟突触输入的持续电流注入导致了一系列动作电位(AP)，在没有SK电导的情况下，这些动作电位随时间的变化很小。神经元的传递函数几乎是线性的，即渐近峰速和细胞内游离钙离子浓度([Ca~(2+)](I))都是输入电流的近似线性函数。加入对[Ca~(2+)]高度非线性依赖的SK电导，(Leinders和Vijverberg，1992)。弗卢格斯拱门。422：223-232；科勒、赫希伯格、邦德、肯齐、玛丽昂、梅利和阿德尔曼。1996年。科学。273：1709-1714)引起了显著的时间依赖的尖峰频率适应，并将神经元的传递函数从线性改变为对数。此外，神经元通过规则的尖峰反应的输入范围增加了2.2倍。这些结果可以用SK电导的激活引起的电池电阻的分流来解释。结果可能是，某些形式(例如，声音或光)的刺激与刺激强度的感知(费克纳定律)之间的对数关系具有细胞基础，即SK电导参与这些刺激的处理。
We made a computational model of a single neuron to study the effect of the small conductance (SK) Ca2+-dependent K+ channel on spike frequency adaptation. The model neuron comprised a Na+ conductance, a Ca2+ conductance, and two Ca2+-independent K+ conductances, as well as a small and a large (BK) Ca2+-activated K+ conductance, a Ca2+ pump, and mechanisms for Ca2+ buffering and diffusion. Sustained current injection that simulated synaptic input resulted in a train of action potentials (APs) which in the absence of the SK conductance showed very little adaptation with time. The transfer function of the neuron was nearly linear, i.e., both asymptotic spike rate as well as the intracellular free Ca2+ concentration ([Ca2+](i)) were approximately linear functions of the input current. Adding an SK conductance with a steep nonlinear dependence on [Ca2+], (Leinders and Vijverberg, 1992. Pflugers Arch. 422:223-232; Kohler, Hirschberg, Bond, Kinzie, Marrion, Maylie, and Adelman. 1996. Science. 273:1709-1714) caused a marked time-dependent spike frequency adaptation and changed the transfer function of the neuron from linear to logarithmic. Moreover, the input range the neuron responded to with regular spiking increased by a factor of 2.2. These results can be explained by a shunt of the cell resistance caused by the activation of the SK conductance. It might turn out that the logarithmic relationships between the stimuli of some modalities (e.g., sound or light) and the perception of the stimulus intensity (Fechner's law) have a cellular basis in the involvement of SK conductances in the processing of these stimuli.