Kawada Toru, Shishido Toshiaki, Inagaki Masashi, Zheng Can, Yanagiya Yusuke, Uemura Kazunori, Sugimachi Masaru, Sunagawa Kenji
Department of Cardiovascular Dynamics, National Cardiovascular Center Research Institute, Suita, 565-8565 Japan.
Jpn J Physiol. 2002 Feb;52(1):21-9. doi: 10.2170/jjphysiol.52.21.
Two types of closed-loop perturbations can be applied to the arterial baroreflex system. The first (P(D1)) is introduced into the baroreceptors without a direct effect on arterial pressure (AP), whereas the second (P(D2)) initially affects AP. Neck suction and hemorrhage are examples of P(D1) and P(D2), respectively. To estimate the baroreflex open-loop gain (G(Baro)) without knowing the absolute magnitudes of P(D1) and P(D2), we explored a new strategy to estimate G(Baro) by combining P(D1) and P(D2) in a baroreflex equilibrium diagram. In this diagram, the neural arc presents the input-output relationship between baroreceptor pressure input and sympathetic nerve activity (SNA). The peripheral arc presents the input-output relationship between SNA and AP. In 8 anesthetized rabbits, we estimated G(Baro) by multiplying the slopes of the peripheral arc determined from P(D1) and the neural arc determined from P(D2). We also estimated G(Baro) by a conventional open-loop analysis. The G(Baro) values estimated by the equilibrium diagram and the open-loop analysis showed a positive correlation (y = 0.80x + 0.22, r(2) = 0.95) and a standard error of estimate of 0.21 across the animals. We conclude that G(Baro) was estimated well by combining P(D1) and P(D2) in the equilibrium diagram.
两种类型的闭环扰动可应用于动脉压力感受器反射系统。第一种（P(D1)）作用于压力感受器，而对动脉血压（AP）无直接影响，而第二种（P(D2)）最初会影响AP。颈部吸引和出血分别是P(D1)和P(D2)的实例。为了在不知道P(D1)和P(D2)绝对大小的情况下估计压力感受器反射开环增益（G(Baro)），我们探索了一种新策略，通过在压力感受器反射平衡图中将P(D1)和P(D2)相结合来估计G(Baro)。在该图中，神经弧表示压力感受器压力输入与交感神经活动（SNA）之间的输入-输出关系。外周弧表示SNA与AP之间的输入-输出关系。在8只麻醉兔中，我们通过将由P(D1)确定的外周弧斜率与由P(D2)确定的神经弧斜率相乘来估计G(Baro)。我们还通过传统的开环分析来估计G(Baro)。通过平衡图和开环分析估计的G(Baro)值呈正相关（y = 0.80x + 0.22，r(2) = 0.95），且在所有动物中的估计标准误差为0.21。我们得出结论，通过在平衡图中将P(D1)和P(D2)相结合能够很好地估计G(Baro)。
