Experience affects exercise-induced changes in catecholamines, glucose, and FFA

Abstract

The interference of the experimental conditions on the exercise-induced alterations in plasma catecholamines, plasma free fatty acids, and glucose and insulin concentrations was investigated in rats. Exercise consisted of strenuous swimming against a countercurrent (0.22 m/s) for 15 min in a pool with water of 33 degrees C. Before, during, and after swimming, blood samples were taken through a permanent heart catheter. The blood component levels in rats that were confronted with exercise for the very first time were compared with the levels in rats that were well accustomed to the exercise conditions. The very first time rats swam caused an enhanced release of epinephrine from the adrenal medulla and a reduced output of norepinephrine from the sympathetic nerve endings. Furthermore, in the first time swim group, blood glucose levels were higher and plasma free fatty acid concentrations were lower compared with the well-accustomed animals. There were no differences in plasma insulin concentrations. It is concluded that the experimental conditions may interfere considerably with the hormonal and metabolic response to exercise. Furthermore the results reinforce the idea that the two parts of the sympathoadrenal system are functionally and metabolically dissociated.

Metabolic and hormonal responses to hypothalamic administration of norfenfluramine in rats

“…Further evidence for a role of serotonergic mechanisms in the PVN in the sympathoadrenal response to stress derives from Experiment 3, in which infusion of NFFL into the PVN markedly reduced the exercise-induced increase of plasma NE levels. These results are in concert with our recent findings that emotional stress leads to a reduction in the outflow of neuronal NE during exercise (38).…”

Efeito de um programa de exercício físico moderado em ratos de diferentes modelos de obesidade

“…Nossos resultados demonstram que o exercício físico aplicado pode ser considerado como atividade física metabolicamente aeróbia, por consumir uma significativa parcela de tecido adiposo como substrato energético. Previamente estes resultados foram observados em roedores, programados ou não para a obesidade (FRIEDMAN et al, 1997;SCOMPARIN et al, 2006;PATTERSON et al, 2008 (SCHEURINK et al, 1989;SCOMPARIN et al, 2006). Dessa forma, pelo menos em parte, podese atribuir a redução no acúmulo tecidual de gordura à estimulação do SNS dos animais treinados.…”

“…Pesquisas sugerem que o exercício físico pode ser um instrumento terapêutico eficiente para impedir ou atenuar o desenvolvimento da obesidade, pois quando este é desenvolvido o dispêndio energético e o requerimento de ácidos graxos como fonte de energia são maiores (BRAY, 1991;NAGAI et al, 2004). Apesar de durante o exercício físico os níveis sanguíneos de glicose e ácidos graxos livres permanecerem constantes, a produção hepática de glicose e a lipólise no tecido adiposo estão aumentados, processos esses que são facilitados principalmente, pela redução da secreção de insulina e aumento da atividade do sistema nervoso simpático (SNS) (SCHEURINK et al, 1989).…”

The effect of dietary protein source on biochemical indices of stress in stress-susceptible pigs

“…1974;Anderson 1979 (Axelrod and Reisine 1984), the tVl/pigs experienced a gteater neuroendocrine stress response to th€ iniiiat blood sampling stressor' These results also differentiate the porcine neuroendocrine and SNS in response to stress. After six weekly blood sampling stressors, the nn pigs demonstrated the greatest ACTH response to the stressoi, suggesting that while the 1/1/ pigs seemed to adapt to the stressJf the nn pigs had more difficulty' Marple and Cassens (1973) and Sebranek et al (1973) to ACTH stimulation of the zona fasciculata tissue of the adrenal medulla causing synthesis and release of cortisol (Axelrod and Reseine 1984 Marple and Cassens (1973) and Sebranek et al (1973) were more likely to identify elevations in plasma cortisol due to the duration of the stressor imposed on the animals. In contrast to the present results, Schaefer et al (1990a) …”