title: D4 receptor deficiency in mice has limited effects on impulsivity and novelty seeking.
abstract: Alleles of the human dopamine D(4) receptor (D(4)R) gene (DRD4.7) have repeatedly been found to correlate with novelty seeking, substance abuse, pathological gambling, and attention-deficit hyperactivity disorder (ADHD). If these various psychopathologies are a result of attenuated D(4)R-mediated signaling, mice lacking D(4)Rs (D(4)KO) should be more impulsive than wild-type (WT) mice and exhibit more novelty seeking. However, in our study, D(4)KO and WT mice showed similar levels of impulsivity as measured by delay discounting performance and response inhibition on a Go/No-go test, suggesting that D(4)R-mediated signaling may not affect impulsivity. D(4)KO mice were more active than WT mice in the first 5 min of a novel open field test, suggesting greater novelty seeking. For both genotypes, more impulsive mice habituated less in the novel open field. These data suggest that the absence of D(4)Rs is not sufficient to cause psychopathologies associated with heightened impulsivity and novelty seeking.
authors.affiliation: Oregon National Primate Research Center, Division of Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States.
authors.forename: C M
authors.initials: CM
authors.lastname: Helms
authors.forename: N R
authors.initials: NR
authors.lastname: Gubner
authors.forename: C J
authors.initials: CJ
authors.lastname: Wilhelm
authors.forename: S H
authors.initials: SH
authors.lastname: Mitchell
authors.forename: D K
authors.initials: DK
authors.lastname: Grandy
mesh_terms: D000818:Animals; D003463:Cues; D005106:Exploratory Behavior / Q000502:physiology*; D005838:Genotype; D007175:Impulsive Behavior / Q000235:genetics* / Q000523:psychology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009043:Motor Activity / Q000502:physiology; D011110:Polymorphism, Genetic; D011597:Psychomotor Performance / Q000502:physiology; D050638:Receptors, Dopamine D4 / Q000172:deficiency* / Q000235:genetics
chemical_list: D050638:Receptors, Dopamine D4