title: Calibration of baroreflex equilibrium diagram based on exogenous pressor agents in chronic heart failure rats.
abstract: A baroreflex equilibrium diagram describes the relation between input pressure and sympathetic nerve activity (SNA) and that between SNA and arterial pressure (AP). To calibrate the SNA axis (abscissa) of the baroreflex equilibrium diagram, the AP response to intravenous bolus injections of phenylephrine (0.2-50 μg/kg) or norepinephrine (NE, 0.02-5 μg/kg) was examined in normal control rats (NC, n = 9) and rats with chronic heart failure (CHF, n = 6). The maximum slope of the dose-effect curve was significantly smaller in the CHF group than in the NC group (57.3 ± 5.2 vs 80.9 ± 6.3 mmHg/decade for phenylephrine, 60.2 ± 7.8 vs 80.4 ± 5.9 mmHg/decade for NE; P < 0.01). The CHF/NC ratio of the maximum slope was used to calibrate SNA. While the calibrated baroreflex equilibrium diagram showed increased maximum SNA and operating-point SNA in CHF rats compared with NC rats, the magnitude of increase was smaller than that expected from the excess plasma NE concentration in CHF rats. Plasma NE concentration in the CHF group could be disproportionally high relative to SNA.
authors.affiliation: Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Kawada
authors.affiliation: Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan.
authors.forename: Meihua
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan. ; Department of Artificial Organ Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sata
authors.affiliation: Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan.
authors.forename: Can
authors.initials: C
authors.lastname: Zheng
authors.affiliation: Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Turner
authors.affiliation: Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Shimizu
authors.affiliation: Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan. ; Department of Artificial Organ Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Sugimachi
keywords: arterial pressure; carotid sinus baroreflex; norepinephrine; open-loop analysis; phenylephrine