Publicover N G, Sanders K M
Department of Physiology, University of Nevada School of Medicine, Reno 89557.
Am J Physiol. 1989 Feb;256(2 Pt 1):G265-74. doi: 10.1152/ajpgi.1989.256.2.G265.
Mathematical models based on relaxation oscillators have heavily influenced the terminology and experimental designs of investigations in gastrointestinal motility for nearly two decades. Relaxation oscillator equations have been used to stimulate the electrical activities of the esophagus, stomach, small intestine, colon, and rectosigmoid region. It has been suggested that many attributes of gastrointestinal electrical activity cannot be adequately explained by classic "core-conductor" or "cable" models of excitation and conduction. This article critically reviews the relaxation oscillator model and provides an explanation for each of the putative inadequacies of core-conductor theory. Furthermore, we question whether relaxation oscillator equations are able to simulate the waveforms of gastrointestinal slow waves, alterations in waveform in response to drugs or electrical stimulation, patterns of slow-wave activity when stimulated at physiological frequencies, prolonged periods of constant resting membrane potential between gastric slow waves and electrotonic spread into inactive regions. We conclude that the relaxation oscillator equations do not fully describe gastrointestinal electrical activity; excitation and propagation can be modeled by a theory that provides for morphological features, ionic conductances, and other elements included in the cable equations.
近二十年来，基于弛豫振荡器的数学模型对胃肠动力研究的术语和实验设计产生了重大影响。弛豫振荡器方程已被用于刺激食管、胃、小肠、结肠和直肠乙状结肠区域的电活动。有人提出，胃肠电活动的许多特性无法用经典的“核心导体”或“电缆”兴奋与传导模型来充分解释。本文对弛豫振荡器模型进行了批判性综述，并对核心导体理论的每个假定不足之处给出了解释。此外，我们质疑弛豫振荡器方程是否能够模拟胃肠慢波的波形、对药物或电刺激的波形变化、在生理频率刺激时的慢波活动模式、胃慢波之间长时间恒定的静息膜电位以及电紧张性扩布到非活动区域。我们得出结论，弛豫振荡器方程不能完全描述胃肠电活动；兴奋和传播可以用一种考虑了形态特征、离子电导和电缆方程中包含的其他元素的理论来建模。
