Abstract：
The precise mechanism behind the supply of adenosine triphosphate (ATP) to approximately half of the presynaptic release sites in axons that lack a stationary mitochondrion is not fully understood. This paper presents a mathematical model designed to simulate the transient ATP concentration in presynaptic en passant boutons. The model is utilized to investigate how the ATP concentration responds to increased ATP demand during neuronal firing in boutons with a stationary mitochondrion and those without one. The analysis suggests that neuron firing may cause oscillations in the ATP concentrations, with peak-to-peak amplitudes ranging from 0.06% to 5% of their average values. However, this does not deplete boutons lacking a mitochondrion of ATP; for physiologically relevant values of model parameters, their concentration remains approximately 3.75 times higher than the minimum concentration required for synaptic activity. The variance in average ATP concentrations between boutons containing a stationary mitochondrion and those lacking one ranges from 0.3% to 0.8%, contingent on the distance between the boutons. The model indicates that diffusion-driven ATP transport is rapid enough to adequately supply ATP molecules to boutons lacking a stationary mitochondrion.
摘要：
在轴突大约一半的突触前释放位点中缺乏固定线粒体的确切机制，以及这些缺乏固定线粒体的位点如何接收ATP，没有完全理解。本文提出了一个数学模型，旨在模拟突触前通过boutons中的瞬时ATP浓度。该模型用于研究在具有固定线粒体和没有线粒体的boutons中神经元放电过程中，ATP浓度如何响应ATP需求的增加。分析表明，神经元放电可能会引起ATP浓度的振荡，峰峰值的范围为平均值的0.06%至5%。然而,这不会耗尽缺乏ATP线粒体的boutons；对于模型参数的生理相关值，它们的浓度仍然比突触活动所需的最低浓度高约3.75倍。含有固定线粒体的boutons和缺乏线粒体的boutons之间的平均ATP浓度差异在0.3％至0.8％之间。取决于boutons之间的距离。该模型表明，扩散驱动的ATP运输足够快，可以向缺乏固定线粒体的boutons充分提供ATP分子。
