NITRIC OXIDE AND CA(2+) DYNAMICS IN CARDIOMYOCYTES: INFLUENCE OF EXERCISE CAPACITY

作者：Drummond Lucas Rios; Carneiro Junior Miguel Araujo; Lauton Santos Sandra; Aggum Capttini Luciano dos Santos; Ribeiro Mesquita Thassio Ricardo; Cruz Jader dos Santos; Coimbra Candido Celso; Lemos Virginia Soares; Natali Antonio Jose; Primola Gomes Thales Nicolau^*

来源：Revista Brasileira de Medicina do Esporte, 2016, 22(1): 31-34.

DOI：10.1590/1517-869220162201143904

• NG-Nitroarginine methyl ester
• physical fitness
• myocytes
• cardiac
• calcium

Introduction: The intrinsic capacity to aerobic exercise is associated with cardiac inotropism. On the other hand, the contribution of nitric oxide (NO) as an intracellular messenger on Ca2+ dynamics remains unknown in rats with different intrinsic capacities to exercise. Objective: To evaluate whether NO modulates differently Ca2+ intracellular transient and spontaneous Ca2+ releases (sparks) in cardiomyocytes of rats with different intrinsic capacities to exercise. Methods: Male Wistar rats were selected as standard-performance (SP) and high-performance (HP), according to the exercise capacity until fatigue, assessed through a treadmill progressive stress test. Cardiomyocytes of rats were used to determine Ca2+ intracellular transient and Ca2+ sparks evaluated using confocal microscope. To estimate NO contribution, a NO synthase inhibitor (L-NAME, 100 mu M) was used. Data were analyzed through two-way ANOVA followed by Tukey's post hoc test and expressed as means +/- SEM. Results: Cardiomyocytes of HP rats exhibited higher Ca2+ transient amplitude compared to SP. However, L-NAME increased Ca2+ transient amplitude only in SP rats. No differences were found in Ca2+ transient decay time constant (tau) in cardiomyocytes of SP and HP rats. However, administration of L-NAME caused reduction of tau in cardiomyocytes of both groups. Lower amplitude and frequency of Ca2+ sparks were found in cardiomyocytes of HS rats compared to SP group. Administration of L-NAME increased the amplitude of Ca2+ sparks in cardiomyocytes of the HP group. Conclusion: NO modulates Ca2+ transient and Ca2+ sparks in cardiomyocytes of rats with different intrinsic exercise capacities.

• 出版日期2016-2