Modulation of Myocardial Stiffness by beta-Adrenergic Stimulation Its Role in Normal and Failing Heart

• Type: Article in International Scientific Journal
• Date: 2011

Authors

Falcao Pires, I (Author) FMUP; Fontes Sousa, AP (Author) ICBAS; Lopes Conceicao, L (Author) Other; Bras Silva, C (Author) FMUP; Leite Moreira, AF (Author) FMUP

Journal

Title: Physiological Research

Vol. 60 No. 4

Pages: 599-609

ISSN: 0862-8408

Publisher: Akademie Ved Ceske Republiky

Indexing

ISI Web of Knowledge - 5 Citations

ISI Web of Science

Scopus - 5 Citations

Pubmed / Medline

Scientific classification

CORDIS: Health sciences

FOS: Medical and Health sciences > Basic medicine

Other information

Authenticus ID: P-002-ZBW

Abstract (EN): The acute effects of ß-adrenergic stimulation on myocardial stiffness were evaluated. New-Zealand white rabbits were treated with saline (control group) or doxorubicin to induce heart failure (HF) (DOXO-HF group). Effects of isoprenaline (10 -10-1 -5 M), a non-selective ß-adrenergic agonist, were tested in papillary muscles from both groups. In the control group, the effects of isoprenaline were also evaluated in the presence of a damaged endocardial endothelium, atenolol (ßi-adrenoceptor antagonist), ICI-118551 (ßz-adrenoceptor antagonist), KT-5720 (PKA inhibitor), L-NNA (NO-synthase inhibitor), or indomethacin (cyclooxygenase inhibitor). Passive length-tension relations were constructed before and after adding isoprenaline (10 -5 M). In the control group, isoprenaline increased resting muscle length up to 1.017±0.006 L/L max. Correction of resting muscle length to its initial value resulted in a 28.5±3.1% decrease of resting tension, indicating decreased muscle stiffness, as confirmed by the isoprenaline-induced right-downward shift of the passive lengthtension relation. These effects were modulated by ßr and ß 2adrenoceptors and PKA. In DOXO-HF group, the effect on myocardial stiffness was significantly decreased. We conclude that ß-adrenergic stimulation is a relevant mechanism of acute neurohumoral modulation of the diastolic function. Furthermore, this study clarifies the mechanisms by which myocardial stiffness is decreased. © 2011 Institute of Physiology v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic.

Language: English

Type (Professor's evaluation): Scientific

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No. of pages: 11