Differential behavioral and neurochemical effects of exercise, reboxetine and citalopram with the forced swim test.
OBJECTIVE
In this study, we investigated whether short-term exercise, known to promote hippocampal brain-derived neurotrophic factor (BDNF) expression, would also enhance activity in the Porsolt forced swim test (FST), a model for assessing antidepressant efficacy. We also wished to determine whether exercise combined with antidepressants would be more effective at modifying behavior in the FST than either intervention alone. In parallel with this, we also expected that these interventions would preserve post-stress levels of BDNF, and that antidepressants designed to selectively enhance noradrenergic or serotonergic neurotransmission (reboxetine or citalopram, respectively) would have differential effects on behavior and BDNF expression.


METHODS
Male Sprague-Dawley rats were treated with exercise (voluntary wheel running), reboxetine, citalopram, or the combination of exercise and each antidepressant, for 1 week. At the end of this period, a subset of animals from each treatment group underwent the FST. Post-stress levels of hippocampal BDNF mRNA were then quantified via in situ hybridization.


RESULTS
Our results indicate that while both exercise and antidepressant treatment preserved post-stress levels of hippocampal BDNF mRNA, each intervention led to a unique behavioral profile in the FST. We found that antidepressant treatment increased swimming time in the FST, but that exercise decreased swimming time. While the combination of reboxetine-plus-exercise led to an increase in climbing and diving, citalopram-plus-exercise reduced these behaviors.


CONCLUSIONS
It is possible that active behaviors during the FST, though specific to antidepressant medications, may not reflect increased hippocampal BDNF expression or other survival- associated benefits.
Arunrut
Teda
T
Department of Biological Sciences, California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032, United States.
Alejandre
Hilda
H
Chen
Michael
M
Cha
Joseph
J
Russo-Neustadt
Amelia
A
D000818:Animals; D018687:Antidepressive Agents, Second-Generation / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects*; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics; D015283:Citalopram / Q000494:pharmacology*; D017403:In Situ Hybridization; D008297:Male; D009025:Morpholines / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077593:Reboxetine; D013550:Swimming
D018687:Antidepressive Agents, Second-Generation; D019208:Brain-Derived Neurotrophic Factor; D009025:Morpholines; D012333:RNA, Messenger; D015283:Citalopram; D000077593:Reboxetine