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Swimming training increases cardiac vagal activity and induces cardiac hypertrophy in rats
Medeiros, A; Oliveira, E. M; Gianolla, R; Casarini, D. E; Negrão, C. E; Brum, P. C.
  • Medeiros, A; Universidade de São Paulo. Escola de Educação Física e Esporte. Departamento de Biodinâmica do Movimento do Corpo Humano. São Paulo. BR
  • Oliveira, E. M; Universidade de São Paulo. Escola de Educação Física e Esporte. Departamento de Biodinâmica do Movimento do Corpo Humano. São Paulo. BR
  • Gianolla, R; Universidade de São Paulo. Escola de Educação Física e Esporte. Departamento de Biodinâmica do Movimento do Corpo Humano. São Paulo. BR
  • Casarini, D. E; Universidade Federal de São Paulo. Escola Paulista de Medicina. Hospital do Rim e Hipertensão. Divisão de Nefrologia. São Paulo. BR
  • Negrão, C. E; Universidade de São Paulo. Escola de Educação Física e Esporte. Departamento de Biodinâmica do Movimento do Corpo Humano. São Paulo. BR
  • Brum, P. C; Universidade de São Paulo. Escola de Educação Física e Esporte. Departamento de Biodinâmica do Movimento do Corpo Humano. São Paulo. BR
Braz. j. med. biol. res ; 37(12): 1909-1917, Dec. 2004. tab, graf
Article Dans Anglais | LILACS | ID: lil-388058
ABSTRACT
The effect of swimming training (ST) on vagal and sympathetic cardiac effects was investigated in sedentary (S, N = 12) and trained (T, N = 12) male Wistar rats (200-220 g). ST consisted of 60-min swimming sessions 5 days/week for 8 weeks, with a 5 percent body weight load attached to the tail. The effect of the autonomic nervous system in generating training-induced resting bradycardia (RB) was examined indirectly after cardiac muscarinic and adrenergic receptor blockade. Cardiac hypertrophy was evaluated by cardiac weight and myocyte morphometry. Plasma catecholamine concentrations and citrate synthase activity in soleus muscle were also determined in both groups. Resting heart rate was significantly reduced in T rats (355 ± 16 vs 330 ± 20 bpm). RB was associated with a significantly increased cardiac vagal effect in T rats (103 ± 25 vs 158 ± 40 bpm), since the sympathetic cardiac effect and intrinsic heart rate were similar for the two groups. Likewise, no significant difference was observed for plasma catecholamine concentrations between S and T rats. In T rats, left ventricle weight (13 percent) and myocyte dimension (21 percent) were significantly increased, suggesting cardiac hypertrophy. Skeletal muscle citrate synthase activity was significantly increased by 52 percent in T rats, indicating endurance conditioning. These data suggest that RB induced by ST is mainly mediated parasympathetically and differs from other training modes, like running, that seems to mainly decrease intrinsic heart rate in rats. The increased cardiac vagal activity associated with ST is of clinical relevance, since both are related to increased life expectancy and prevention of cardiac events.
Sujets)
Texte intégral: Disponible Indice: LILAS (Amériques) Sujet Principal: Conditionnement physique d'animal / Natation / Système nerveux sympathique / Nerf vague / Rythme cardiaque Type d'étude: Etude d'étiologie Limites du sujet: Animaux langue: Anglais Texte intégral: Braz. j. med. biol. res Thème du journal: Biologie / Médicament Année: 2004 Type: Article Pays d'affiliation: Brésil Institution/Pays d'affiliation: Universidade Federal de São Paulo/BR / Universidade de São Paulo/BR

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Texte intégral: Disponible Indice: LILAS (Amériques) Sujet Principal: Conditionnement physique d'animal / Natation / Système nerveux sympathique / Nerf vague / Rythme cardiaque Type d'étude: Etude d'étiologie Limites du sujet: Animaux langue: Anglais Texte intégral: Braz. j. med. biol. res Thème du journal: Biologie / Médicament Année: 2004 Type: Article Pays d'affiliation: Brésil Institution/Pays d'affiliation: Universidade Federal de São Paulo/BR / Universidade de São Paulo/BR