title: Dopamine D1/D2 receptors do not mediate the expression of conditioned place preference induced by the aftereffect of wheel running.
abstract: BACKGROUND
  Rats lever-press for access to running wheels suggesting that wheel running by itself is reinforcing. Furthermore, pairings of an episode of wheel running and subsequent confinement in a specific environment can establish a conditioned place preference (CPP). This finding implies that the reinforcing effects of wheel running outlast the actual occurrence of physical activity, a phenomenon referred to as aftereffect of wheel running. Aftereffect-induced CPP involves Pavlovian conditioning, i.e. repeated pairings of the aftereffect of wheel running with a specific environment creates a learned association between aftereffect and environment and, in turn, a preference for that environment. Given the involvement of dopamine systems in mediating effects of Pavlovian stimuli on appetitive behavior, a role of dopamine in mediating aftereffect-induced CPP seems plausible. Here we assessed whether the mixed D1/D2 receptor antagonist flupenthixol (0.25 mg/kg, i.p.) can block the expression of an aftereffect-induced CPP.
  
  
  RESULTS
  In line with earlier studies, our results demonstrate that rats displayed a conditioned preference for environments paired with the aftereffect of wheel running and further show that the magnitude of CPP was not related to the wheel running rate. Furthermore, we found that flupenthixol (0.25 mg/kg, i.p.) reduced locomotor activity but did not attenuate the expression of an aftereffect-induced CPP.
  
  
  CONCLUSIONS
  The expression of a CPP produced by the aftereffect of wheel running seems not to depend on dopamine D1/D2 receptor activation.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Trost
authors.affiliation: Department Animal Physiology, University of Stuttgart, Pfaffenwaldring 57, Stuttgart, D-70550, Germany. hauber@bio.uni-stuttgart.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hauber
mesh_terms: D000818:Animals; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology*; D018492:Dopamine Antagonists / Q000494:pharmacology; D005475:Flupenthixol / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology*; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D012420:Running / Q000502:physiology; D013028:Space Perception / Q000187:drug effects / Q000502:physiology*
chemical_list: D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D005475:Flupenthixol