Vascular β-adrenergic receptor system is dysfunctional after myocardial infarction

Mohamed A. Gaballa, Andrea Eckhart, Walter J. Koch, Steven Goldman

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

We identified abnormalities in the vascular β-adrenergic receptor (β-AR) signaling pathway in heart failure after myocardial infarction (MI). To examine these abnormalities, we measured β-AR-mediated hemodynamics, vascular reactivity, and the vascular β-AR molecular signaling components in rats with heart failure after MI. Six weeks after MI, these rats had an increased left ventricular (LV) end-diastolic pressure, decreased LV systolic pressure, and decreased rate of LV pressure change (dP/dt). LV dP/dt responses to isoproterenol were shifted downward, although the responses for systemic vascular resistance were shifted upward in heart failure rats (P < 0.05). Isoproterenol- and IBMX-induced vasorelaxations were blunted in heart failure rats (P < 0.05) with no change in the forskolin-mediated vasorelaxation. These changes were associated with the following alterations in β-AR signaling (P < 0.05): decreases in β-AR density (aorta: 58.7 ± 6.0 vs. 35.7 ± 1.9 fmol/mg membrane protein; carotid: 29.6 ± 5.6 vs. 18.0 ± 3.9 fmol/mg membrane protein, n = 5), increases in G protein-coupled receptor kinase activity levels (relative phosphorimage counts of 191 ± 39 vs. 259 ± 26 in the aorta and 115 ± 30 vs. 202 ± 7 in the carotid artery, n = 5), and decreases in cGMP and cAMP in the carotid artery (0.85 ± 0.10 vs. 0.31 ± 0.06 pmol/mg protein and 2.3 ± 0.3 vs. 1.2 ± 0.1 pmol/mg protein, n = 5) with no change in Gαs or Gαi in the aorta. Thus in heart failure there are abnormalities in the vascular β-AR system that are similar to those seen in the myocardium. This suggests a common neurohormonal mechanism and raises the possibility that treatment in heart failure focused on the myocardium may also affect the vasculature.

Original languageEnglish (US)
Pages (from-to)H1129-H1135
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume280
Issue number3 49-3
DOIs
StatePublished - 2001

Keywords

  • G protein
  • Heart failure
  • Hemodynamics, cAMP/cGMP
  • β-adrenergic receptor-coupled kinase

ASJC Scopus subject areas

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

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