Preservation of the baroreceptor heart rate reflex by chemical sympathectomy in experimental heart failure

Luca Mircoli, Luigi Fedele, Marica Benetti, Giovanni Battista Bolla, Alberto Radaelli, Stefano Perlini, Alberto U. Ferrari

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Abstract

Background - The mechanisms underlying impaired baroreflex sensitivity in congestive heart failure (CHF) are incompletely understood. The purpose of the present study was to test the hypothesis that this alteration depends on the marked degree of sympathetic overactivity known to characterize the CHF syndrome. Methods and Results - Eight-week-old rats were subjected to induction of postmyocardial infarction CHF obtained by coronary ligation (Lig), chronic chemical sympathectomy by 6-hydroxydopamine (Sx), both interventions (Sx-Lig), or neither intervention (Veh-Sham, sham surgery, and vehicle administration). Four weeks after infarction, in conscious state, baroreflex sensitivity was assessed from the bradycardic responses to graded phenylephrine-induced elevations in blood pressure (BP). Left ventricular (LV) diameter was assessed by echocardiography, and plasma catecholamines were assayed to estimate sympathetic activity. Lungs were eventually excised and weighed (LW). CHF was associated with the following: (1) no changes in BP and heart rate; (2) sympathetic overactivity (norepinephrine, 320.2±53.8 pg/mL for Veh-Lig versus 173.4±20.5 pg/mL for Veh-Sham, P

Original languageEnglish
Pages (from-to)866-872
Number of pages7
JournalCirculation
Volume106
Issue number7
DOIs
Publication statusPublished - Aug 13 2002

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Keywords

  • Baroreceptors
  • Heart failure
  • Nervous system
  • Sympathetic

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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