title: Dissection of the Effects of Quercetin on Mouse Myocardium.
abstract: Quercetin is a plant flavonoid with several biological activities. This study aimed to describe quercetin effects on contractile and electrophysiological properties of the cardiac muscle as well as on calcium handling. Quercetin elicited positive inotropism that was significantly reduced by propranolol indicating an involvement of the sympathetic nervous system. In cardiomyocytes, 30 μM quercetin increased ICa,Lat 0 mV from -0.95 ± 0.01 A/F to -1.21 ± 0.08 A/F. The membrane potential at which 50% of the channels are activated (V0.5) shifted towards more negative potentials from -13.06 ± 1.52 mV to -19.26 ± 1.72 mV and did not alter the slope factor. Furthermore, quercetin increased [Ca2+]itransient by 28% when compared to control. Quercetin accelerated [Ca2+]itransient decay time, which could be attributed to SERCA activation. In resting cardiomyocytes, quercetin did not change amplitude or frequency of Ca2+sparks. In isolated heart, quercetin increased heart rate and decreased PRi, QTc and duration of the QRS complex. Thus, we showed that quercetin activates β-adrenoceptors, leading to increased L-type Ca2+current and cell-wide intracellular Ca2+transient without visible changes in Ca2+sparks.
authors.affiliation: Laboratory of Heart Biophysics, Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil.
authors.forename: Michel Santana
authors.initials: MS
authors.lastname: Santos
authors.affiliation: Laboratory of Heart Biophysics, Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil.|Department of Physiotherapy, Federal University of Sergipe, São Cristóvão, SE, Brazil.
authors.forename: Evaleide Diniz
authors.initials: ED
authors.lastname: Oliveira
authors.affiliation: Excitable Membranes Laboratory, Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Artur
authors.initials: A
authors.lastname: Santos-Miranda
authors.affiliation: Excitable Membranes Laboratory, Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Jader Santos
authors.initials: JS
authors.lastname: Cruz
authors.affiliation: Laboratory of Biophysics and Pharmacology of the Heart, Department of Education, Campus XII, University of the State of Bahia, Guanambi, BA, Brazil.
authors.forename: Antônio Nei Santana
authors.initials: ANS
authors.lastname: Gondim
authors.affiliation: Laboratory of Heart Biophysics, Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil.
authors.forename: José Evaldo Rodrigues
authors.initials: JER
authors.lastname: Menezes-Filho
authors.affiliation: Laboratory of Heart Biophysics, Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil.
authors.forename: Diego Santos
authors.initials: DS
authors.lastname: Souza
authors.affiliation: Excitable Membranes Laboratory, Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Leidiane
authors.initials: L
authors.lastname: Pinho-da-Silva
authors.affiliation: Cardiomyocyte Intracellular Signaling Laboratory, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Itamar Couto Guedes
authors.initials: ICG
authors.lastname: Jesus
authors.affiliation: Department of Biophysics, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Danilo
authors.initials: D
authors.lastname: Roman-Campos
authors.affiliation: Cardiomyocyte Intracellular Signaling Laboratory, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Silvia
authors.initials: S
authors.lastname: Guatimosim
authors.affiliation: Cardiomyocyte Intracellular Signaling Laboratory, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Aline
authors.initials: A
authors.lastname: Lara
authors.affiliation: Laboratory of Heart Biophysics, Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil.
authors.forename: Eduardo Antônio
authors.initials: EA
authors.lastname: Conde-Garcia
authors.affiliation: Laboratory of Heart Biophysics, Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil.
authors.forename: Carla Maria Lins
authors.initials: CML
authors.lastname: Vasconcelos
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000502:physiology; D004562:Electrocardiography / Q000187:drug effects; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D011794:Quercetin / Q000494:pharmacology*
chemical_list: D020746:Calcium Channels, L-Type; D011794:Quercetin; D002118:Calcium