title: Cardiac Dysfunction Induced by Obesity Is Not Related to β-Adrenergic System Impairment at the Receptor-Signalling Pathway.
abstract: Obesity has been shown to impair myocardial performance. Some factors have been suggested as responsible for possible cardiac abnormalities in models of obesity, among them beta-adrenergic (βA) system, an important mechanism of regulation of myocardial contraction and relaxation. The objective of present study was to evaluate the involvement of βA system components in myocardial dysfunction induced by obesity. Thirty-day-old male Wistar rats were distributed in control (C, n = 25) and obese (Ob, n = 25) groups. The C group was fed a standard diet and Ob group was fed four unsaturated high-fat diets for 15 weeks. Cardiac function was evaluated by isolated papillary muscle preparation and βA system evaluated by using cumulative concentrations of isoproterenol and Western blot. After 15 weeks, the Ob rats developed higher adiposity index than C rats and several comorbidities; however, were not associated with changes in systolic blood pressure. Obesity caused structural changes and the myocardial responsiveness to post-rest contraction stimulus and increased extracellular calcium (Ca2+) was compromised. There were no changes in cardiac function between groups after βA stimulation. The obesity was not accompanied by changes in protein expression of G protein subunit alpha (Gsα) and βA receptors (β1AR and β2AR). In conclusion, the myocardial dysfunction caused by unsaturated high-fat diet-induced obesity, after 15 weeks, is not related to βAR system impairment at the receptor-signalling pathway.
authors.affiliation: Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil.
authors.forename: Artur Junio Togneri
authors.initials: AJ
authors.lastname: Ferron
authors.affiliation: Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil.
authors.forename: Bruno Barcellos
authors.initials: BB
authors.lastname: Jacobsen
authors.affiliation: Department of Clinical and Cardiology, School of Medicine, UNESP- Univ. Estadual Paulista, Botucatu, São Paulo, Brazil.
authors.forename: Paula Grippa
authors.initials: PG
authors.lastname: Sant'Ana
authors.affiliation: Department of Clinical and Cardiology, School of Medicine, UNESP- Univ. Estadual Paulista, Botucatu, São Paulo, Brazil.
authors.forename: Dijon Henrique Salomé
authors.initials: DH
authors.lastname: de Campos
authors.affiliation: Department of Clinical and Cardiology, School of Medicine, UNESP- Univ. Estadual Paulista, Botucatu, São Paulo, Brazil.
authors.forename: Loreta Casquel
authors.initials: LC
authors.lastname: de Tomasi
authors.affiliation: Instituto de Ciências da Saúde, Federal University of Mato Grosso, Sinop, Mato Grosso, Brazil.
authors.forename: Renata de Azevedo Mello
authors.initials: Rde A
authors.lastname: Luvizotto
authors.affiliation: Department of Clinical and Cardiology, School of Medicine, UNESP- Univ. Estadual Paulista, Botucatu, São Paulo, Brazil.
authors.forename: Antonio Carlos
authors.initials: AC
authors.lastname: Cicogna
authors.affiliation: Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil.
authors.forename: André Soares
authors.initials: AS
authors.lastname: Leopoldo
authors.affiliation: Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Lima-Leopoldo
mesh_terms: D050154:Adiposity / Q000187:drug effects; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D015153:Blotting, Western; D002118:Calcium / Q000494:pharmacology; D059305:Diet, High-Fat / Q000009:adverse effects; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism; D006321:Heart / Q000187:drug effects / Q000503:physiopathology*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009765:Obesity / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D010210:Papillary Muscles / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors
chemical_list: D000318:Adrenergic beta-Agonists; D011943:Receptors, Adrenergic, beta; D019205:GTP-Binding Protein alpha Subunits, Gs; D007545:Isoproterenol; D002118:Calcium