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Effects of exercise training on excitation-contraction coupling, calcium dynamics and protein expression in the heart of the Neotropical fish &ITBrycon amazonicus&IT

Texto completo
Rissoli, Rafael Zanelli [1] ; Vasconcelos, Eliton da Silva [1] ; Rantin, Francisco Tadeu [1] ; Kalinin, Ana Lucia [1]
Número total de Autores: 4
Afiliação do(s) autor(es):
[1] Univ Fed Sao Carlos, Dept Physiol Sci, Sao Carlos, SP - Brazil
Número total de Afiliações: 1
Tipo de documento: Artigo Científico
Citações Web of Science: 0

Matrinxa (Brycon amazonicus) is a great swimming performance teleost fish from the Amazon basin. However, the possible cardiac adaptations of this ability are still unknown. Therefore, the aim of the present work was to investigate the effects of prolonged exercise (EX group - 60 days under 0.4 BL.s(-1)) on ventricular contractility by (i) in-vitro analysis of contractility comparing the relative roles of sodium/calcium exchanger (NCX) and sarcoplasmic reticulum (SR) in the excitation-contraction (E-C) coupling and (ii) molecular analysis of NCX, sarcoplasmic reticulum Ca2+ ATPase (SERCA2) and phospholamban (PLB) expression and quantification. The exercise training significantly improved twitch tension, cardiac pumping capacity and the contraction rate when compared to controls (CT). Inhibition of the NCX function, replacing Na+ by Li+ in the physiological solutions, diminished cardiac contractility in the EX group, reduced all analyzed parameters under both high and low stimulation frequencies. The SR blockage, using 10 mu M ryanodine, caused similar to 50% tension reduction in CT at most analyzed frequencies while in EX, reductions (34-54%) were only found at higher frequencies. SR inhibition also decreased contraction and relaxation rates in both groups. Additionally, higher post-rest contraction values were recorded for EX, indicating an increase in SR Ca2+ loading. Higher NCX and PLB expression rates and lower SERCA2 rates were found in EX. Our data indicate that matrinxa presents a modulation in E-C coupling after exercise-training, enhancing the SR function under higher frequencies. This was the first study to functionally analyze the effects of swimming-induced exercise on fish cardiac E-C coupling. (AU)

Processo FAPESP: 13/17410-7 - Efeitos do exercício prolongado sobre a contratilidade cardíaca de uma espécie de peixe migratória, Brycon amazonicus (Teleostei, Characidae)
Beneficiário:Rafael Zanelli Rissoli
Linha de fomento: Bolsas no Brasil - Doutorado
Processo FAPESP: 08/57712-4 - Instituto Nacional de Pesquisas em Fisiologia Comparada
Beneficiário:Augusto Shinya Abe
Linha de fomento: Auxílio à Pesquisa - Temático