Elstad Maja, Toska Karin, Walløe Lars
Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1103 Blindern, N-0317 Oslo, Norway.
J Physiol. 2002 Sep 1;543(Pt 2):719-28. doi: 10.1113/jphysiol.2002.019422.
We have tested whether the cardiovascular changes at the onset of exercise could be simulated only by an increase in the baroreflex set point and locally induced vasodilatation in the exercising muscles. The mathematical model consists of a heart, a linear elastic arterial reservoir and two parallel resistive vascular beds. The arterial baroreflex loop is modelled by three separate time domain processing objects, each with its own gain, time constant and delay. These are intended to simulate the action of a sympathetic signal to the peripheral vascular bed, a parasympathetic signal to the heart and a sympathetic signal to the heart. We used this model with previously published experimental data to estimate the unknown parameters in the reflex control loop. In all 10 subjects and in the global averaged response, the short-term cardiovascular responses were adequately simulated by using individual sets of parameters in the model. An increase in the baroreflex set point and locally induced vasodilatation in the exercising muscles can explain almost all of the cardiovascular changes in the recorded variables (mean arterial pressure, RR interval and stroke volume) at the onset of exercise.
我们测试了运动开始时的心血管变化是否仅能通过压力反射设定点的增加以及运动肌肉局部诱导的血管舒张来模拟。该数学模型由心脏、线性弹性动脉贮器和两个平行的阻力血管床组成。动脉压力反射环路由三个独立的时域处理对象建模，每个对象都有自己的增益、时间常数和延迟。这些旨在模拟交感神经信号对外周血管床的作用、副交感神经信号对心脏的作用以及交感神经信号对心脏的作用。我们使用该模型和先前发表的实验数据来估计反射控制环路中的未知参数。在所有10名受试者以及总体平均反应中，通过在模型中使用单独的参数集，能够充分模拟短期心血管反应。压力反射设定点的增加以及运动肌肉局部诱导的血管舒张几乎可以解释运动开始时记录变量（平均动脉压、RR间期和每搏输出量）中的所有心血管变化。
