Journal article
Reduction of heart rate by chronic beta1-adrenoceptor blockade promotes growth of arterioles and preserves coronary perfusion reserve in postinfarcted heart
American journal of physiology. Heart and circulatory physiology, Vol.288(6), pp.H2684-H2693
06/2005
DOI: 10.1152/ajpheart.01047.2004
PMID: 15681710
Abstract
Adequate growth of coronary vasculature in the remaining left ventricular (LV) myocardium after myocardial infarction (post-MI) is a crucial factor for myocyte survival and performance. We previously demonstrated that post-MI coronary angiogenesis can be stimulated by bradycardia induced with the ATP-sensitive K(+) channel antagonist alinidine. In this study, we tested the hypothesis that heart rate reduction with beta-blockade may also induce coronary growth in the post-MI heart. Transmural MI was induced in 12-mo-old male Sprague-Dawley rats by occlusion of the left anterior descending coronary artery. Bradycardia was induced by administration of the beta-adrenoceptor blocker atenolol (AT) via drinking water (30 mg/day). Three groups of rats were compared: 1) control/sham (C/SH), 2) MI, and 3) MI + AT. In the MI + AT rats, heart rate was consistently reduced by 25-28% compared with C/SH rats. At 4 wk after left anterior descending coronary ligation, infarct size was similar in MI and MI + AT rats (67.1 and 61.5%, respectively), whereas a greater ventricular hypertrophy occurred in bradycardic rats, as indicated by a higher ventricular weight-to-body weight ratio (3.4 +/- 0.1 vs. 2.8 +/- 0.1 mg/g in MI rats). Analysis of LV function revealed a smaller drop in ejection fraction in the MI + AT than in the MI group ( approximately 24 vs. approximately 35%). Furthermore, in MI + AT rats, maximal coronary conductance and coronary perfusion reserve were significantly improved compared with the MI group. The better myocardial perfusion indexes in MI + AT rats were associated with a greater increase in arteriolar length density than in the MI group. Thus chronic reduction of heart rate induced with beta-selective blockade promotes growth of coronary arterioles and, thereby, facilitates regional myocardial perfusion in post-MI hearts.
Details
- Title: Subtitle
- Reduction of heart rate by chronic beta1-adrenoceptor blockade promotes growth of arterioles and preserves coronary perfusion reserve in postinfarcted heart
- Creators
- Eduard I Dedkov - Dept. of Anatomy and Cell Biology, Carver College of Medicine, 1-402 Bowen Science Bldg., Univ. of Iowa, Iowa City, IA 52242, USA. eduard-dedkov@uiowa.eduLance P ChristensenRobert M WeissRobert J Tomanek
- Resource Type
- Journal article
- Publication Details
- American journal of physiology. Heart and circulatory physiology, Vol.288(6), pp.H2684-H2693
- DOI
- 10.1152/ajpheart.01047.2004
- PMID
- 15681710
- ISSN
- 0363-6135
- eISSN
- 1522-1539
- Grant note
- R01-HL-62587 / NHLBI NIH HHS
- Language
- English
- Date published
- 06/2005
- Academic Unit
- Anatomy and Cell Biology; Cardiovascular Medicine; Internal Medicine
- Record Identifier
- 9984094878502771
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