Salt-induced plasticity in cardiopulmonary baroreceptor reflexes in salt-resistant hypertensive patients

Bruno Trimarco, Giuseppe Lembo, Bruno Ricciardelli, Nicola De Luca, Virgilio Rendina, Gianluigi Condorelli, Massimo Volpe

Research output: Contribution to journalArticlepeer-review

Abstract

To investigate the effects of salt loading on cardiopulmonary and arterial baroreceptor reflexes, 34 hypertensive patients underwent two 4-day periods with different dietary sodium intakes (70 and 370 meq/day). The patients were classified as salt-sensitive or salt-resistant depending on whether the mean arterial pressure value obtained on day 4 of high salt intake did or did not increase by 8% or more. In 22 patients cardiopulmonary and carotid baroreceptor reflexes were assessed during each dietary period by measuring the reflex responses to the application of -10 mm Hg lower body negative pressure and of +60 mm Hg increase in neck tissue pressure. Salt-resistant patients (n = 16) retained less sodium than salt-sensitive patients (n=6) and showed a reduction in plasma norepinephrine and forearm vascular resistance during high sodium intake, whereas the salt-sensitive patients did not. During low sodium diet, no significant differences could be detected in the reflex responses to cardiopulmonary and carotid baroreceptor unloading between the two groups. High salt diet, however, potentiated the gain of cardiopulmonary baroreceptor reflex, which was expressed as the increase in plasma norepinephrine or forearm vascular resistance per millimeter of mercury decrease in pulmonary capillary wedge pressure, only in the salt-resistant hypertensive patients. In addition, the atrial natriuretic factor response to changes in pulmonary capillary wedge pressure was significantly enhanced by high salt intake only in the salt-resistant hypertensive patients. The reflex responses to carotid baroreceptor unloading were unaffected by salt loading in either group. In the remaining 12 patients, the hemodynamic effects of graded lower body negative pressure (-5, -10, -15 mm Hg) and neck tissue positive pressure (+30, +45, +60 mm Hg) were tested for both diets. Again, high salt intake significantly potentiated the cardiopulmonary baroreceptor reflex gain, expressed as the slope of the linear correlation between the changes in forearm vascular resistance (mm Hg/mI/min/100 g) and pulmonary capillary wedge pressure (mm Hg), in salt-resistant (from 3.8±0.9 to 7.2±1.0,p

Original languageEnglish
Pages (from-to)483-493
Number of pages11
JournalHypertension
Volume18
Issue number4
Publication statusPublished - Oct 1991

Keywords

  • Atrial natriuretic factor
  • Baroreceptors
  • Plasma renin activity
  • Sodium-dependent hypertension
  • Sympathetic nervous system

ASJC Scopus subject areas

  • Internal Medicine

Fingerprint Dive into the research topics of 'Salt-induced plasticity in cardiopulmonary baroreceptor reflexes in salt-resistant hypertensive patients'. Together they form a unique fingerprint.

Cite this