Enhanced nitric oxide bioavailability in coronary arteries prevents the onset of heart failure in rats with myocardial infarction

Autor(es)

Couto, Gisele K. ^[1] ; Britt, Luiz Roberto G. ^[1] ; Mill, Jose G. ^[2] ; Rossoni, Luciana V. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, Sao Paulo, SP - Brazil

^[2] Univ Fed Espirito Santo, Dept Physiol Sci, Vitoria - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY; v. 86, p. 110-120, SEP 2015.
• Citações Web of Science: 15

Resumo

Aim: The endothelium, mainly via nitric oxide (NO) release, adjusts the coronary flow. Cardiac function is closely linked to blood flow; thus, we tested the hypothesis that NO modulation in coronary arteries could be differentially adjusted after myocardial infarction (MI) in the presence or absence of heart failure (HF). Methods and results: Four weeks after coronary occlusion, the infarcted rats were subdivided into rats without (MI) or with HF signs according to haemodynamic parameters. The septal coronary arteries were subsequently used to perform functional and molecular experiments. Acetylcholine (ACh)-induced relaxation was decreased in the coronary arteries following HF, whereas it was enhanced in the arteries of the MI compared with those of SHAM-operated (SO) rats. The relaxation induced by the NO donor was similar among the groups. NO production, which was evaluated by 4,5-diaminofluorescein diacetate, was reduced in the coronary arteries of the HF group and increased in the arteries with MI after ACh-induced stimulation. HF coronary arteries exhibited oxidative stress, which was evaluated via ethidium bromide-positive nuclei, whereas it was decreased in MI. To evaluate the mechanisms involved in the enhanced ACh-induced relaxation in the arteries following MI, certain septal coronary arteries were pre-incubated with L-NAME (a nonselective NO synthase (NOS) inhibitor), 7-NI (a selective neuronal NOS (nNOS) inhibitor) or LY294002 (a PI3-Idnase inhibitor). L-NAME and LY294002 reduced ACh-induced relaxation in the MI and SO rats; however, these effects were greater in the MI arteries. 7-NI reduced only the ACh-relaxation in MI. In addition, the eNOS, nNOS, Akt, and superoxide dismutase isoform protein expressions were greater in the coronary arteries of the MI than in those of the SO groups. Conclusion: Our data suggested that endothelial function was closely related to cardiac function after coronary occlusion. The coronary arteries from the HF rats exhibited reduced NO bioavailability, whereas the MI rats exhibited increased NO bioavailability because of increased eNOS/nNOS/PI3-kinase/Akt pathway and a reduction in ROS generation. These results suggest that enhanced NO modulation can prevent the onset of HF. (C) 2015 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 10/50048-1 - Bases celulares e funcionais do exercício físico na doença cardiovascular
• Beneficiário: Carlos Eduardo Negrão
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 07/55030-0 - Estudo comparativo da funcao vascular em arterias de resistencia dos leitos mesenterico, muscular esqueletico e coronariano de ratos em uma fase aguda e cronica pos-infarto do miocardio.
• Beneficiário: Gisele Kruger Couto
• Modalidade de apoio: Bolsas no Brasil - Doutorado