Volume 111, Nº 2, August 2018
DOI: http://www.dx.doi.org/10.5935/abc.20180113
ORIGINAL ARTICLE
Physical Exercise and Regulation of Intracellular Calcium in Cardiomyocytes of Hypertensive Rats
Joel Alves Rodrigues
Thales Nicolau Prímola-Gomes
Leôncio Lopes Soares
Tiago Ferreira Leal
Clara Nóbrega
Danillo Laviola Pedrosa
Leonardo Mateus Teixeira Rezende
Edilamar Menezes de Oliveira
Antonio Jose Natali
Figure 1 – (A) Time to exhaustion of normotensive and hypertensive before (pre) and after (post) training. (B) Running velocity during training sessions. TN: trained normotensive; TH: trained hypertensive. Data are expressed as mean ± SD of 8 animals in each group. * compared with TN (pre); # compared with TH (pre) (p < 0.05).
Abstract
Background: Regulation of intracellular calcium (Ca2+) in cardiomyocytes is altered by hypertension; and aerobic exercise brings benefits to hypertensive individuals.
Objective: To verify the effects of aerobic exercise training on contractility and intracellular calcium (Ca2+) transients of cardiomyocytes and on the expression of microRNA 214 (miR-214) in the left ventricle of spontaneously hypertensive rats (SHR).
Methods: SHR and normotensive Wistar rats of 16 weeks were divided into 4 groups –sedentary hypertensive (SH); trained hypertensive (TH); sedentary normotensive (SN); and trained normotensive (TN). Animals of the TH and TN groups were subjected to treadmill running program, 5 days/week, 1 hour/day at 60-70% of maximum running velocity for 8 weeks. We adopted a p ≤ 0.05 as significance level for all comparisons.
Results: Exercise training reduced systolic arterial pressure in hypertensive rats. In normotensive rats, exercise training reduced the time to 50% cell relaxation and the time to peak contraction and increased the time to 50% decay of the intracellular Ca2+ transients. In SHR, exercise increased the amplitude and reduced the time to 50% decay of Ca2+ transients. Exercise training increased the expression of miR-214 in hypertensive rats only.
Conclusion: The aerobic training applied in this study increased the availability of intracellular Ca2+ and accelerated the sequestration of these ions in left ventricular myocytes of hypertensive rats, despite increased expression of miR-214 and maintenance of cell contractility. (Arq Bras Cardiol. 2018; 111(2):172-179)
Keywords: Hypertension; Exercise; Rats; Calcium Signaling; Intracellular Calcium; Sensing Proteins.
