开环颈动脉窦压力感受性反射特性

Characteristics of Open-loop Carotid Sinus Baroreflex

目的 :研究开环颈动脉窦压力感受性反射 (CSR)的反射规律和反射特性参数的定量方法。方法 :在Wistar大鼠麻醉下孤离颈动脉窦 ,用多道仪同步记录平均动脉压和窦内压 ;分别应用四参数型和五参数型logistic函数拟合实验数据 ;基于数学推导提出了反射特征参数如阈压、饱和压的确定方法。结果 :随着窦内压的递增或递减 ,动脉血压遵循不对称S形变化规律 ;与四参数型lo gistic函数相比 ,五参数型函数拟合显著减少拟合方差 ;与过去有关文献所采用的对阈压和饱和压的确定方法相比 ,本文提出的方法所得值比较接近于实验观察值。结论 :CSR开环反射具有不对称S形特性 ,反射参数的定量分析方法应作重新确定。

Objective: This project was designed to study the open-loop characteristics of the carotid sinus reflex (CSR) and the determination of its characteristic parameters. Methods: After the carotid sinus was isolated from the systemic circulation in anesthetized Wistar rats, the mean arterial pressure and the intracarotid sinus pressure were simultaneously recorded. Data were fitted respectively into the logistic equations with four or five parameters. The determination of the threshold and saturation was deduced on biomathmatics. Results: With the changes of the intracarotid sinus pressures, the change of mean arterial pressure was asymmetrically sigmoid. The application of the five-parameter model significantly reduced the mean squares of the fit, showing that the five-parameter logistic fit is more suitable for describing the open-loop baroreflex function than the four-parameter logistic fit. Compared with the methods described in previous literatures, the values of the threshold and saturation obtained by the method presented in the present study were closer to the observed intervals.Conclusion: Open-loop CSR may have an asymmetric sigmoidal curve,and its characteristic parameters could be re-defined.