Chon K H, Chen Y M, Holstein-Rathlou N H, Marmarelis V Z
Division of Health Science and Technology, Harvard-Massachusetts Institute of Technology (MIT), Cambridge, USA.
IEEE Trans Biomed Eng. 1998 Mar;45(3):342-53. doi: 10.1109/10.661159.
We compared the dynamic characteristics in renal autoregulation of blood flow of normotensive Sprague-Dawley rats (SDR) and spontaneously hypertensive rats (SHR), using both linear and nonlinear systems analysis. Linear analysis yielded only limited information about the differences in dynamics between SDR and SHR. The predictive ability, as determined by normalized mean-square errors (NMSE), of a third-order Volterra model is better than for a linear model. This decrease in NMSE with a third-order model from that of a linear model is especially evident at frequencies below 0.2 Hz. Furthermore, NMSE are significantly higher in SHR than SDR, suggesting a more complex nonlinear system in SHR. The contribution of the third-order kernel in describing the dynamics of renal autoregulation in arterial blood pressure and blood flow was found to be important. Moreover, we have identified the presence of nonlinear interactions between the oscillatory components of the myogenic mechanism and tubuloglomerular feedback (TGF) at the level of whole kidney blood flow in SDR. An interaction between these two mechanisms had previously been revealed for SDR only at the single nephron level. However, nonlinear interactions between the myogenic and TGF mechanisms are not detected for SHR.
我们使用线性和非线性系统分析方法，比较了正常血压的斯普拉格-道利大鼠（SDR）和自发性高血压大鼠（SHR）肾血流自动调节的动态特征。线性分析仅提供了关于SDR和SHR之间动力学差异的有限信息。由归一化均方误差（NMSE）确定的三阶沃尔泰拉模型的预测能力优于线性模型。在低于0.2Hz的频率下，三阶模型的NMSE相对于线性模型的降低尤为明显。此外，SHR的NMSE显著高于SDR，表明SHR中存在更复杂的非线性系统。发现三阶核在描述动脉血压和血流中肾自动调节的动力学方面具有重要作用。此外，我们已经确定在SDR的全肾血流水平上，肌源机制和肾小管-肾小球反馈（TGF）的振荡成分之间存在非线性相互作用。此前仅在单个肾单位水平上揭示了SDR中这两种机制之间的相互作用。然而，未检测到SHR的肌源机制和TGF机制之间存在非线性相互作用。
