Efeito da cafeina na função cardiaca de ratos treinados

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

The effect of caffeine on the cardiovascular system has been largely investigated. However, conflictant results have been found, some investigators showed that caffeine increases blood pressure after caffeine increases blood pressure after caffeine treatment. Therefore, the aim of this work was to investigate the effect of caffeine treatment on the cardiac parameters in sedentary and trained rats by swim training program. The swim training program consisted of 5 days a week, 60 min each session for 8 weeks of training. After that, the animaIs were anesthetized and the hearts were isolated for dose-response curves for isoproterenol, adenosine and endothelin-1 were obtained. Plasma lactate leveI, blood pressure and heart rate were also evaluated. Heart rate, body weight and lactate plasma levels were significantly lower in trained group showing that the physical training employed in our study was effective. Caffeine treatment for 8 weeks produced an increase of blood pressure that it was prevent by physical training. In isolated heart, basal coronary flow was markedly increases in trained and caffeine treated group. Caffeine by itself elevates the basal heart rate in both groups (sedentary or trained). Isoproterenol determined a positive chronotropic response similarly in all studied groups while a desensitization of inotropic response were seen for isoproterenol in isolated heart ITomcaffeine/treated group. . The potency for adenosine was significantly higher in both trained groups for the negative chronotropic response. However, adenosine was not able to induce any negative inotropic response in isolated heart from caffeine/ treated animaIs (sedentary and trained) showing that different population of adenosine receptors mediate the inotropic and chronotropic response rat isolated heart. No changes were found for the actions of endothelin-1 in all studied groups. In conclusion, caffeine treatment associated with swim physical training induces a desensitization of inotropic response and supersensitivity of negative chronotropic response to adenosine in swimtraining groups. Consumed before the exercise program, caffeine is considerate a stimulant.

ASSUNTO(S)

cafeina coração rato - exercicios

ACESSO AO ARTIGO

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