Abstract
The purpose of this experiment was to examine the effects of administration of serotonergic
(5-HT) agonist and antagonist drugs on run-time to exhaustion (RUN-EXH) in male and
female rats. RUN-EXH was reduced (p<0.05) in a dose related manner by increasing dosages
of quipazine dimaleate (QD: general 5-HT agonist) (0-5mg·kg-1i.p.) administered immediately prior to exercise (treadmill running at 20 m · min-1 and 5% grade). Conversely, RUN-EXH was increased (p<0.05) by the greatest dosage
of LY 53,857 (LY: 5-HT1c and 5-HT2 antagonist) (1.5mg·kg-1i.p.). Drug effects were similar in male and female rats. The negative effects of
QD administration on RUN-EXH were not attenuated by administration of the peripherally
restricted antagonist, xylamidine tosylate (up to 200ug·kg-1i.p.). The results of this investigation indicated that fatigue during prolonged exercise
can be influenced by direct pharmacological administration of a serotonergic agonist
and antagonist and that the mechanisms underlying these effects are likely to be central
(brain) in nature.
Key words
Central fatigue - serotonin - exhaustion
