Physical conditioning in rats influences the central and peripheral catecholamine responses to sustained exercise

Abstract

We have investigated the effect of treadmill running in rats (25m.min-1 using a 3% gradient; for 1 h or 2 h) on the cortical extracellular concentrations of noradrenaline (NA) and its main metabolites-3,4-dihydroxyphenylglycol and 3-methoxy-4-hydroxyphenylglycol- and the plasma adrenaline (A) and NA concentrations in relation to prior physical conditioning (1 or 2-h running.day-1 for 12 days). Cortical microdialysates and peripheral blood were collected during 1-h resting, 1-h or 2-h running and for 1 h after exercise. Catecholamines and their metabolites were quantitated using high performance liquid chromatography with electrochemical detection. Treadmill running stimulated concomitantly peripheral catecholamine secretion and central noradrenergic activity, i.e. NA turnover and release. The effect extended into the recovery period even more as the duration of the run increased. Prior physical conditioning greatly influenced the central and peripheral catecholamine responses: the 1-h trained rats experienced the 2-h run as a stressful new event eliciting great long-lasting catecholamine responses, whereas the 2-h trained rats exhibited a progressive sustained catecholamine increase with an earlier onset of the central NA release. The data are discussed in relation to the psychological and intellectual effects of exercise and physical fitness in humans. In addition, the positive correlation found between the central noradrenergic activation and peripheral A secretion confirmed and extended our previous observations in exercising men and gave support to the hypothesis that the elevation of circulating A can be a relevant factor mediating--directly or indirectly--the exercise-induced central effects.

Treadmill exercise does not change gene expression of adrenal catecholamine biosynthetic enzymes in chronically stressed rats

“…Also, the treadmill running stimulated concomitantly peripheral catecholamines secretion and central noradrenergic activity, i.e. NA turnover and release (Pagliari and Peyrin 1995). In this study, we observed that CSITR provoked a decreased morning CORT concentration in the plasma.…”

Exercise in the treatment of depression

“…Increased extraneuronal metabolism of norepinephrine (NE) has been observed, as have increased levels of NE and its metabolites in the frontal cortex and hippocampus [8,9]. NE turnover and release also are shown to be increased during exercise [10,11]. Similarly, increased serotonin synthesis, metabolism [12], and release [13][14][15] also have been observed.…”

Does long-term physical exercise counteract age-related Purkinje cell loss? A stereological study of rat cerebellum

“…Physical exercise influences the brain through many processes, including some that apparently promote neuron survival. Changes in the synthesis and metabolism of neurotransmitters (Dey et al, 1992;Meeusen and Meirleir, 1995;Pagliari and Peyrin, 1995), and classical neurotrophic factors (Neeper et al, 1995(Neeper et al, , 1996, following physical exercise have been reported. In addition to the traditionally defined neurotrophic factors, a diverse set of factors have been reported to have growth-promoting effects in the central nervous system.…”

“…Local actions include 1) increased neuronal (synaptic) activity (Vissing et al, 1996) and blood flow (Jørgensen et al, 1992) in a number of brain regions; 2) changes in the synthesis and the metabolism of neurotransmitters (Dey et al, 1992;Meeusen and Meirleir, 1995;Pagliari and Peyrin, 1995), neurotrophic factors (Neeper et al, 1995(Neeper et al, , 1996, and antioxidant enzymes (So-mani and Husain, 1996); and 3) local structural changes, such as increased capillary density (Isaacks et al, 1992). Any of the above-mentioned factors might affect the normal aging of the brain according to the holistic network theory of aging, in which the entire orchestrated process of multiple endogenous and exogenous damaging and protective agents and processes are assumed to determine the capability of the system to preserve homeostasis (Kowald and Kirkwood, 1994).…”