Effect of arterial compliance on carotid sinus baroreceptor reflex control of the circulation

Jeffrey T. Potts, Tetsuo Hatanaka, Artin A. Shoukas

Research output: Contribution to journalArticlepeer-review

Abstract

Capacitive properties of the arterial and venous segments of the peripheral circulation are important in the regulation of cardiac output and arterial blood pressure. We examined whether an acute increase in arterial compliance (C8) would alter carotid sinus baroreflex control of the circulation. Eight mongrel dogs were anesthetized with pentobarbital sodium, and the carotid sinus regions were isolated and perfused with nonpulsatile pressures. Open-loop baroreflex response curves for systemic arterial pressure (SAP), heart rate (HR), aortic blood flow (ABF), peripheral vascular resistance (PVR), and left ventricular (LV) contractility were obtained when carotid sinus pressure (CSP) was changed in 25-mmHg steps between 50 and 200 mmHg under a control condition and when C(a) was increased by including two hydraulic compliant chambers to the arterial circulation (C(S) 1.72 ml/mmHg and C(L) 5.05 ml/mmHg). The compliant chambers significantly increased C(a) and altered the ratio of arterial to venous compliance (C(a)/C(v)). Changes in C(a)/C(v) significantly decreased the maximal open-loop baroreflex gain (G(max)) for SAP (-2.3± 0.5, -1.6 ± 0.3, and -1.1 ± 0.2 mmHg/mmHg, control vs. C(S) vs. C(L), P < 0.05). G(max) for ABF was decreased by C(S) (0.9 ± 0.2 vs. -0.3 ± 0.1 ml · kg-1 · min-1, control vs. C(S), P < 0.05), and C(L) reversed the reflex changes in ABF (G(max): +0.6 ± 0.3 ml · kg-1 · min-1). G(max) for HR, PVR, and LV contractility was not altered when C(a) was increased (P > 0.05). These findings indicate that an increase in C(a) changes C(a)/C(v) and alters carotid baroreflex control of SAP by modifying the ABF response. We conclude that a change in C(a)/C(v) affects the reflex control of the circulation by altering the distribution of blood volume between the arterial and venous circulations.

Original languageEnglish (US)
Pages (from-to)H988-H1000
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume270
Issue number3 39-3
DOIs
StatePublished - 1996

Keywords

  • arterial-to- venous compliance ratio
  • blood volume distribution
  • cardiac output
  • systemic arterial compliance
  • systemic venous compliance
  • venous return

ASJC Scopus subject areas

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

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