ABC | Volume 111, Nº2, August 2018

Original Article Rodrigues et al Physical exercise and calcium regulation Arq Bras Cardiol. 2018; 111(2):172-179 Figure 3 – Cardiomyocyte contractility in normotensive and hypertensive animals. (A) Contraction amplitude expressed as percentage of change in cell length at rest (%c.l.r.) after electrical stimulation at 1HZ; (B) time to peak concentration; (C) time to 50% of relaxation; SN, sedentary normotensive; TN, trained normotensive; SH, sedentary hypertensive; TH, trained hypertensive. Data as mean ± SD of 60-80 cells in each group. * compared with SN; # compared with SN; + compared with TH (p < 0.05). A C B 15 10 5 0 SN SH TN TH SN SH TN TH SN SH TN TH Contraction amplitude (c.l.r.) Time to peak contraction Time to 50% of relaxation 200 100 150 50 0 200 100 300 0 *#+ reduced miR-214 expression and increased SERCA2a expression. These adaptations were associated with faster relaxation of myocytes isolated from the left ventricle of trained animals. Similar results showing reduction in miR‑214 expression and elevated SERCA2a expression were also reported in infarcted rats subjected to resistance training. 13 Therefore, little is known about the effects of aerobic exercise on hypertensive cardiomyocytes, and further studies are needed to investigate other possible changes associated with intracellular Ca 2+ regulation in the cardiomyocytes of hypertensive rats subjected to aerobic training. Conclusion The aerobic training applied in the present study increased the availability of intracellular Ca 2+ in the myocytes of the left ventricle of hypertensive rats, despite the increased expression of miR-214 and maintenance of cell contractility. Author contributions Conception and design of the research: Rodrigues JA, Prímola-Gomes TN, Natali AJ; Acquisition of data: Rodrigues JA, Soares LL, Leal TF, Nóbrega C, Pedrosa DL, Rezende LMT, Oliveira EM, Natali AJ; Analysis and interpretation of the data: Rodrigues JA, Soares LL, Leal TF, Nóbrega C, Oliveira EM, Natali AJ; Statistical analysis: Rodrigues JA, Soares LL, Leal TF, Nóbrega C, Natali AJ; Obtaining financing: Prímola-Gomes TN, Natali AJ; Writing of the manuscript: Rodrigues JA, Natali AJ; Critical revision of the manuscript for intellectual content: Natali AJ. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding This study was funded by FAPEMIG (APQ-00876-14). Study Association This article is part of the thesis of master submitted by Joel Alves Rodrigues, from Universidade Federal de Viçosa. Ethics approval and consent to participate This study was approved by the Ethics Committee on Animal Experiments of the Colégio Brasileiro de Experimentação Animal (COBEA) under the protocol number 29/2014. 176