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首页> 外文期刊>Journal of Computational Neuroscience >Neuromodulatory changes in short-term synaptic dynamics may be mediated by two distinct mechanisms of presynaptic calcium entry
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Neuromodulatory changes in short-term synaptic dynamics may be mediated by two distinct mechanisms of presynaptic calcium entry

机译：短期突触动力学的神经调节变化可能由突触前钙进入的两种不同机制介导

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摘要

Although synaptic output is known to be modu lated by changes in presynaptic calcium channels, additional pathways for calcium entry into the presynaptic terminal, such as non-selective channels, could contribute to modula tion of short term synaptic dynamics. We address this issue using computational modeling. The neuropeptide proctolin modulates the inhibitory synapse from the lateral pyloric (LP) to the pyloric dilator (PD) neuron, two slow-wave bursting neurons in the pyloric network of the crab Cancer borealis. Proctolin enhances the strength of this synapse and also changes its dynamics. Whereas in control saline the synapse shows depression independent of the amplitude of the presynaptic LP signal, in proctolin, with high-amplitude presynaptic LP stimulation the synapse remains depressing while low-amplitude stimulation causes facilitation. We use simple calcium-dependent release models to explore two alternative mechanisms underlying these modulatory effects. In the first model, proctolin directly targets calcium channels by changing their activation kinetics which results in gradual accumulation of calcium with low-amplitude presynaptic stimulation, leading to facilitation. The second model uses the fact that proctolin is known to activate a non specific cation current I_(MI). In this model, we assume that the MI channels have some permeability to calcium, modeled to be a result of slow conformation change after binding cal cium. This generates a gradual increase in calcium influx into the presynaptic terminals through the modulatory chan nel similar to that described in the first model. Each of these models can explain the modulation of the synapse by proc tolin but with different consequences for network activity.
机译：尽管已知突触输出是由突触前钙通道的变化调节的，但钙进入突触前末端的其他途径（如非选择性通道）可能有助于短期突触动力学的调节。我们使用计算建模解决了这个问题。神经肽的前庭素调节抑制性突触从外侧幽门（LP）到幽门扩张器（PD）神经元，这是蟹癌的幽门网络中的两个慢波爆发神经元。 Proctolin增强了这种突触的强度，并改变了其动力学。而在对照盐水中，突触显示出与突触前LP信号的幅度无关的抑制，而在Proctolin中，通过高振幅突触前LP刺激，突触保持压抑，而低振幅刺激则促进了突触。我们使用简单的钙依赖性释放模型来探索潜在的这些调节作用的两种替代机制。在第一个模型中，通过改变它们的活化动力学，直肠素直接靶向钙通道，这导致钙在低幅度突触前刺激下逐渐积累，从而促进了钙通道的形成。第二种模型利用了事实，即直肠素激活非特异性阳离子电流I_（MI）。在该模型中，我们假设MI通道对钙具有一定的渗透性，其建模是结合钙后缓慢构象变化的结果。这会通过类似于第一个模型中所述的调节通道，使钙流入突触前末端逐渐增加。这些模型中的每一个都可以解释过程蛋白对突触的调节，但对网络活动具有不同的后果。

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  • 来源
    《Journal of Computational Neuroscience》 |2012年第3期|p.573-585|共13页
  • 作者

    Myongkeun Oh; Shunbing Zhao; Victor Matveev; Farzan Nadim;

  • 作者单位

    Department of Mathematical Sciences, New Jersey Institute of Technology,Newark, NJ 07102, USA;

    Department of Biological Sciences, Rutgers University, 195 University Ave.,Newark, NJ 07102, USA;

    Department of Mathematical Sciences, New Jersey Institute of Technology,Newark, NJ 07102, USA;

    Department of Mathematical Sciences, New Jersey Institute of Technology,Newark, NJ 07102, USA,Department of Biological Sciences, Rutgers University, 195 University Ave.,Newark, NJ 07102, USA;

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  • 正文语种 eng
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  • 关键词

    neuromodulation; proctolin; short-term synaptic dynamics; pyloric network;

    机译：神经调节备考短期突触动力学;幽门网络;

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