HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 286/6/H2272    most recent 00787.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Kawada, T. Articles by Sunagawa, K. Search for Related Content PubMed PubMed Citation Articles by Kawada, T. Articles by Sunagawa, K.

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

¹Department of Cardiovascular Dynamics, National Cardiovascular Center Research Institute, Osaka 565-8565; and ²Organization for Pharmaceutical Safety and Research, Tokyo 100-0013, Japan

Submitted 18 August 2003 ; accepted in final form 9 February 2004

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 P₁₆₀, 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 P₁₀₀ (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 P₁₃₀ (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.

systems analysis; transfer function; simulation; carotid sinus baroreflex; nonlinearity

This article has been cited by other articles:

				K. Yamamoto, T. Kawada, A. Kamiya, H. Takaki, T. Shishido, K. Sunagawa, and M. Sugimachi Muscle mechanoreflex augments arterial baroreflex-mediated dynamic sympathetic response to carotid sinus pressure Am J Physiol Heart Circ Physiol, September 1, 2008; 295(3): H1081 - H1089. [Abstract] [Full Text] [PDF]

				V. Orea, R. Kanbar, B. Chapuis, C. Barres, and C. Julien Transfer function analysis between arterial pressure and renal sympathetic nerve activity at cardiac pacing frequencies in the rat J Appl Physiol, March 1, 2007; 102(3): 1034 - 1040. [Abstract] [Full Text] [PDF]