Effects of exercise training on excitation-contraction coupling, calcium dynamics and protein expression in the heart of the Neotropical fish Brycon amazonicus.
Comp Biochem Physiol A Mol Integr Physiol
; 214: 85-93, 2017 12.
Article
en En
| MEDLINE
| ID: mdl-28966144
ABSTRACT
Matrinxã (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 - 60days under 0.4BL·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 10µM ryanodine, caused ~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 matrinxã 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.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Condicionamiento Físico Animal
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Regulación del Desarrollo de la Expresión Génica
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Señalización del Calcio
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Acoplamiento Excitación-Contracción
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Characiformes
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Corazón
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Miocardio
Límite:
Animals
País/Región como asunto:
America do sul
/
Brasil
Idioma:
En
Revista:
Comp Biochem Physiol A Mol Integr Physiol
Asunto de la revista:
BIOLOGIA MOLECULAR
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FISIOLOGIA
Año:
2017
Tipo del documento:
Article
País de afiliación:
Brasil
Pais de publicación:
EEUU
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ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
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EUA
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UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA