Please use this identifier to cite or link to this item: https://hdl.handle.net/10216/61845
Author(s): Falcao Pires, I
Fontes Sousa, AP
Lopes Conceicao, L
Bras Silva, C
Leite Moreira, AF
Title: Modulation of Myocardial Stiffness by beta-Adrenergic Stimulation Its Role in Normal and Failing Heart
Issue Date: 2011
Abstract: 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.
Subject: Ciências da Saúde, Medicina básica
Health sciences, Basic medicine
Scientific areas: Ciências médicas e da saúde::Medicina básica
Medical and Health sciences::Basic medicine
URI: https://repositorio-aberto.up.pt/handle/10216/61845
Document Type: Artigo em Revista Científica Internacional
Rights: openAccess
License: https://creativecommons.org/licenses/by-nc/4.0/
Appears in Collections:FMUP - Artigo em Revista Científica Internacional
ICBAS - Artigo em Revista Científica Internacional

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