Enhanced vascular contractility and diminished coronary artery flow in rats made hypertensive from diet-induced obesity

C. M. Boustany-Kari, M. Gong, W. S. Akers, Z. Guo, L. A. Cassis

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Objective: To determine whether obesity-induced hypertension was associated with alterations in vascular contractility and/or cardiac function. Design: Male Sprague-Dawley rats were fed either a low fat (LF; 11% kcal as fat) or a moderately high fat (MHF; 32% kcal as fat) diet for 11 weeks. Measurements: Body weight; mean arterial pressure; angiotensin peptides; mesenteric contractile response to phenylephrine (PE), potassium chloride (KCl), serotonin, angiotensin II (AngII), calcium chloride; baseline and isoproterenol-induced cardiac contractility; baseline and isoproterenol-induced coronary artery blood flow. Results: Rats fed the MHF diet segregated into obesity-prone (OP) and obesity-resistant (OR) groups. OP rats exhibited elevations in mean arterial pressure (MAP) and elevations in systemic concentrations of angiotensin peptides. Mesenteric arteries from OP rats exhibited a greater contractile response to PE, KCl and serotonin (5-HT). Heightened responses to PE persisted in arteries from OP rats even after normalization of the response to KCl. In contrast, the response of permeabilized mesenteric arteries to a maximal concentration of calcium was similar in rats from each group. Isolated perfused hearts exhibited similar baseline and isoproterenol-induced contractility in rats from each group. However, isoproterenol was unable to increase coronary artery blood flow in hearts from OP rats. Conclusion: Enhanced vascular reactivity may contribute to obesity-induced hypertension, while reductions in coronary artery relaxation would impair the ability of the heart to respond to increased myocardial demand.

Original languageEnglish
Pages (from-to)1652-1659
Number of pages8
JournalInternational Journal of Obesity
Volume31
Issue number11
DOIs
StatePublished - Nov 2007

Bibliographical note

Funding Information:
This research was supported by National Heart Lung and Blood Institute Grant HL-73085 (L Cassis), and through an American Heart Association Grant-in-Aid 0455159B (W Akers).

Keywords

  • Angiotensin
  • Cardiac function
  • Hypertension
  • Vascular contractility

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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