title: Effects of haloperidol, a dopamine D2-like receptor antagonist, on reward-related behaviors in laying hens.
abstract: In order to investigate the involvement of dopaminergic transmission in the regulation of reward-related behaviors in laying hens, the effects of systemic injections of dopamine D2-like receptor antagonist haloperidol (0.3, 0.5, 1.0 and 2.0 mg/kg s.c.) 30 min prior to a conditioned cue signaling a reward were tested and compared to the effects of a saline injection. Head movements and latency to initiate display of anticipatory behavior were significantly affected by 0.3 and 0.5 mg/kg haloperidol, respectively. More hens were found lying down resting prior to the cue at 0.5 mg/kg and higher doses, and increased latency to peck at reward and shorter duration of anticipatory behavior was significant at 2.0 mg/kg. The findings are consistent with the involvement of dopamine in control of reward-related behaviors in laying hens. It is suggested that the lowest dose of haloperidol (0.3 mg/kg) affects reward-related behaviors, whereas the effects of higher doses of haloperidol could be confounded by sedative effects. A high inter- and intra observer agreement in the assessment of head movements together with their dopamine dependency further suggest that this behavior in classical conditioning paradigm represents an indicator of the state of the reward system in laying hens that can be assessed with good reliability.
authors.affiliation: Dept. of Production Animal Clinical Sciences, The Norwegian School of Veterinary Science, P.O. Box 8146 dep., N-0033 Oslo, Norway. randi.moe@nvh.no
authors.forename: Randi Oppermann
authors.initials: RO
authors.lastname: Moe
authors.forename: Janicke
authors.initials: J
authors.lastname: Nordgreen
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Janczak
authors.forename: Berry M
authors.initials: BM
authors.lastname: Spruijt
authors.forename: Lubor
authors.initials: L
authors.lastname: Kostal
authors.forename: Eystein
authors.initials: E
authors.lastname: Skjerve
authors.forename: Adroaldo J
authors.initials: AJ
authors.lastname: Zanella
authors.forename: Morten
authors.initials: M
authors.lastname: Bakken
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D016009:Chi-Square Distribution; D002645:Chickens; D003213:Conditioning, Psychological / Q000187:drug effects; D018492:Dopamine Antagonists / Q000494:pharmacology*; D065127:Dopamine D2 Receptor Antagonists; D005260:Female; D006220:Haloperidol / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D011897:Random Allocation; D012201:Reward
chemical_list: D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D006220:Haloperidol