UBC Theses and Dissertations
Serotonin and exercise Walsh, Michael Leonard
The effects of altering serotonin (5-HT) concentration on physical exercise were investigated in adult, male, hooded rats. The rats were trained to run on a treadmill at a speed of 40 m/min, then subjected to an exhaustive run. Serotonin levels were decreased by para-chlorophenylalanine (300 mg/kg; intragastric) and increased by 5-HT (50 ug; intraventricular). Rats with lowered 5-HT levels had a 30% increase in running time to exhaustion whereas their controls only had a 1% increase. Elevating 5-HT levels decreased running time 44% whereas appropiate controls had a 7% increase in running time. In some animals the effect of exercise on 5-HT levels in the cerebellum, medulla oblongata, hypothalamus, midbrain, striatum, hippocampus, and cortex were measured. When compared to yoked, shocked controls, exercised rats had no difference in the absolute levels of 5-HT except for a lesser amount in the hypothalamus. These results suggest that although exercise did not increase absolute 5-HT levels, changing resting levels of 5-HT can markedly alter subsequent running time to exhaustion.
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