Chon K H, Chen Y M, Marmarelis V Z, Marsh D J, Holstein-Rathlou N H
Department of Biomedical Engineering, University of Southern California, Los Angeles 90033.
Am J Physiol. 1994 Jul;267(1 Pt 2):F160-73. doi: 10.1152/ajprenal.1994.267.1.F160.
Previous studies using linear techniques have provided valuable insights into the dynamic characteristics of whole kidney autoregulation and have led to the general conclusion that the myogenic mechanism and tubuloglomerular feedback (TGF) are highly nonlinear control mechanisms. To explore further the dynamic nature of these nonlinear autoregulatory mechanisms, we introduce the technique of nonlinear modeling using Volterra-Wiener kernels. In the past several years, use of Volterra-Wiener kernels for nonlinear approximation has been most notably applied to neurophysiology. Recent advances in algorithms for computation of the kernels have made this technique more attractive for the study of the dynamics of nonlinear physiological systems, such as the system mediating renal autoregulation. In this study, the general theory and requirements for using this technique are discussed. The feasibility of using the technique on whole kidney pressure and flow data is examined, and a basis for using the Volterra-Wiener kernels to detect interactions between physiological control mechanisms is established. As a result of this method, we have identified the presence of interactions between the oscillating components of the myogenic and the TGF mechanisms at the level of the whole kidney blood flow in normotensive rats. An interaction between these oscillatory components had previously been demonstrated only at the single-nephron level.
以往使用线性技术的研究为全肾自动调节的动态特性提供了有价值的见解，并得出了一般结论，即肌源机制和管球反馈（TGF）是高度非线性的控制机制。为了进一步探索这些非线性自动调节机制的动态本质，我们引入了使用沃尔泰拉-维纳核的非线性建模技术。在过去几年中，沃尔泰拉-维纳核用于非线性逼近最显著地应用于神经生理学。核计算算法的最新进展使该技术对于研究非线性生理系统的动力学（如介导肾自动调节的系统）更具吸引力。在本研究中，讨论了使用该技术的一般理论和要求。研究了将该技术应用于全肾压力和流量数据的可行性，并建立了使用沃尔泰拉-维纳核检测生理控制机制之间相互作用的基础。通过这种方法，我们已经确定在正常血压大鼠的全肾血流水平上，肌源机制和TGF机制的振荡成分之间存在相互作用。此前仅在单肾单位水平证明了这些振荡成分之间的相互作用。
