A derivative-sigmoidal model reproduces operating point-dependent baroreflex neural arc transfer characteristics

Toru Kawada, Kazunori Uemura, Koji Kashihara, Atsunori Kamiya, Masaru Sugimachi, Kenji Sunagawa

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

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 (P70, P100, P130, and P 160, respectively). The transfer gain at 0.01 Hz was significantly smaller at P70 (0.61 ± 0.26) and P160 (0.60 ± 0.25) than at Ploo (1.32 ± 0.42) and P130 (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 P70 (17.6 ± 3.6) and P160 (14.1 ± 4.3) than at P100 (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.

Original languageEnglish
Pages (from-to)H2272-H2279
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume286
Issue number6 55-6
DOIs
Publication statusPublished - Jun 1 2004
Externally publishedYes

Keywords

  • Carotid sinus baroreflex
  • Nonlinearity
  • Simulation
  • Systems analysis
  • Transfer function

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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