A derivative-sigmoidal model reproduces operating point-dependent baroreflex neural arc transfer characteristics
A derivative-sigmoidal model reproduces operating point-dependent baroreflex neural arc transfer characteristics
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DOI：
10.1152/ajpheart.00787.2003
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发表时间：
2004-06-01
影响因子：
4.8
通讯作者：
Sunagawa, K
中科院分区：
文献类型：
--
作者：
Kawada, T;Uemura, K;Sunagawa, K
一个级联模型包括一个衍生物过滤器，然后由一个非线性S形分量再现的压力感受器压力输入传出交感神经活动（SNA）的压力反射神经弧中的传输增益的输入大小依赖性。我们研究了相同的模型是否可以预测由二进制白色噪声输入估计的压力反射神经弧传递特性的工作点依赖性。在8只麻醉家兔中，我们将双侧颈动脉窦从体循环中分离出来，并控制颈动脉窦内压（CSP）。我们估计了从CSP到SNA的线性传递函数，同时在70、100、130和160 mmHg（分别为P-70、P-100、P-130和P-160）之间改变平均CSP。P-70（0.61 +/- 0.26）和P-160（0.60 +/- 0.25）时0.01 Hz时的转移增益显著小于P-100（1.32 +/- 0.42）和P-130（1.36 +/- 0.45）（任意单位/mmHg;平均值+/- SD; P < 0.05）。相比之下，高于0.5 Hz的传输增益值在协议中是相似的。结果，P-70（17.6 +/- 3.6）和P-160（14.1 +/- 4.3）的0.1和0.5 Hz之间增益增加的斜率显著陡于P-100（8.1 +/- 4.4）和P-130（7.4 +/- 6.6）（单位：dB/decade;平均值+/- SD; P < 0.05）。这些结果与导数-S形模型预测的结果一致，其中平均输入压力偏离S形非线性中心主要在低频范围内降低了传递增益。导数-S形模型在功能上再现了动脉压力感受器反射在宽操作范围内的动态SNA调节。
A cascade model comprised of a derivative filter followed by a nonlinear sigmoidal component reproduces the input size dependence of transfer gain in the baroreflex neural arc from baroreceptor pressure input to efferent sympathetic nerve activity (SNA). We examined whether the same model could predict the operating point dependence of the baroreflex neural arc transfer characteristics estimated by a binary white noise input. In eight anesthetized rabbits, we isolated bilateral carotid sinuses from the systemic circulation and controlled intracarotid sinus pressure (CSP). We estimated the linear transfer function from CSP to SNA while varying mean CSP among 70, 100, 130, and 160 mmHg (P-70, P-100, P-130, and P-160, respectively). The transfer gain at 0.01 Hz was significantly smaller at P-70 (0.61 +/- 0.26) and P-160 (0.60 +/- 0.25) than at P-100 (1.32 +/- 0.42) and P-130 (1.36 +/- 0.45) (in arbitrary units/mmHg; means +/- SD; P < 0.05). In contrast, transfer gain values above 0.5 Hz were similar among the protocols. As a result, the slope of increasing gain between 0.1 and 0.5 Hz was significantly steeper at P-70 (17.6 +/- 3.6) and P-160 (14.1 +/- 4.3) than at P-100 (8.1 +/- 4.4) and P-130 (7.4 +/- 6.6) (in dB/decade; means +/- SD; P < 0.05). These results were consistent with those predicted by the derivative-sigmoidal model, where the deviation of mean input pressure from the center of the sigmoidal nonlinearity reduced the transfer gain mainly in the low-frequency range. The derivative-sigmoidal model functionally reproduces the dynamic SNA regulation by the arterial baroreflex over a wide operating range.