Loiselle D S
Biophys J. 1987 Jun;51(6):905-13. doi: 10.1016/S0006-3495(87)83418-5.
A mathematical model of oxygen diffusion into cylindrical papillary muscles is presented. The model partitions total oxygen flux into its simple and myoglobin-facilitated components. The model includes variable sigmoidal, exponential, or hyperbolic functions relating oxygen partial pressure to both fractional myoglobin saturation and rate of oxygen consumption. The behavior of the model was explored for a variety of saturation- and consumption-concentration relations. Facilitation of oxygen transport by myoglobin was considerable as indexed both by the elevation of oxygen partial pressure on the longitudinal axis of the muscle and by the fraction of total oxygen flux at the muscle center contributed by oxymyoglobin. Despite its facilitation of oxygen flux at the muscle center, myoglobin made only a negligible contribution to the total oxygen consumption averaged over the muscle cross-section. Hence the presence of myoglobin fails to explain either the experimentally determined basal metabolism-muscle radius relation or the stretch effect observed in isolated papillary muscle.
本文提出了一个氧气扩散到圆柱形乳头肌的数学模型。该模型将总氧通量分为简单扩散成分和肌红蛋白促进扩散成分。该模型包括将氧分压与肌红蛋白分数饱和度和氧消耗率相关联的可变S形、指数或双曲线函数。针对各种饱和度和消耗浓度关系，对该模型的行为进行了研究。肌红蛋白对氧气运输的促进作用相当显著，这既体现在肌肉纵轴上氧分压的升高，也体现在肌肉中心由氧合肌红蛋白贡献的总氧通量的比例上。尽管肌红蛋白促进了肌肉中心的氧通量，但在整个肌肉横截面上平均的总氧消耗中，肌红蛋白的贡献微不足道。因此，肌红蛋白的存在既无法解释实验确定的基础代谢与肌肉半径的关系，也无法解释在分离的乳头肌中观察到的拉伸效应。
