Exercise is associated with reduction in the anxiogenic effect of mCPP on acoustic startle.
Voluntary exercise has been associated with reduced anxiety across several animal models. Manipulation of central 5-HT can alter anxiety-like behaviors and administration of the 5-HT agonist metachlorophenylpiperazine (mCPP) increases anxiety in rodents and humans. To examine whether the anxiolytic effect of exercise is associated with an alteration in 5-HT systems, we examined the anxiogenic effect of mCPP in exercising and nonexercising mice. C57BL/6J mice were given 2 weeks of free access to either a functioning or nonfunctioning running wheel. Mice were then tested for acoustic startle following systemic injection of either 0, 0.1, 0.3, or 1 mg/kg of mCPP. Consistent with its anxiogenic properties, mCPP produced a dose-dependent increase in acoustic startle in nonexercising mice. However, this anxiogenic effect was blunted in exercising mice. These findings suggest that exercise may help to reduce anxiety by altering 5-HT systems, perhaps by down-regulating postsynaptic 5HT 2B/2C receptors.
Fox
James H
JH
Department of Psychology, University of Vermont, Burlington, VT 05405, USA.
Hammack
Sayamwong E
SE
Falls
William A
WA
D000161:Acoustic Stimulation / Q000379:methods; D000704:Analysis of Variance; D000818:Animals; D001007:Anxiety / Q000139:chemically induced* / Q000534:rehabilitation*; D001522:Behavior, Animal; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010805:Physical Conditioning, Animal / Q000379:methods*; D010879:Piperazines / Q000008:administration & dosage*; D013216:Reflex, Startle / Q000187:drug effects / Q000502:physiology*; D017366:Serotonin Receptor Agonists / Q000008:administration & dosage*
D010879:Piperazines; D017366:Serotonin Receptor Agonists; C015068:1-(3-chlorophenyl)piperazine