title: Topographical Assessment of Ethological and Dopamine Receptor Agonist-Induced Behavioral Phenotype in Mutants with Congenic DARPP-32 'Knockout'.
abstract: Congenic (10 backcrosses into C57BL/6J) mutants with targeted gene deletion of DARPP-32, a neuronal phosphoprotein regarded as an essential mediator of the biological effects of dopamine (DA), were assessed phenotypically using an ethologically based approach that resolves all topographies of behavior in the mouse repertoire. Over initial exploration, female, but not male, DARPP-32 mutants evidenced increased locomotion and decreased grooming, while a decrease in rearing seated was evident in mutants of both genders; continuing assessment over several hours did not reveal additional phenotypic effects. Following challenge with the nonselective DA receptor agonist apomorphine, low doses were associated with reduced levels of sniffing, grooming, total rearing, and rearing seated in DARPP-32 mutants relative to wildtypes; this would suggest some role for DARPP-32 in mediating the biological effects of presynaptic D(2)-like autoreceptor or inhibitory postsynaptic D(2)-like receptor activation. Following challenge with higher doses, while stereotyped sniffing and locomotion with chewing was largely unaltered, the additional murine response of Straub tail was essentially abolished in DARPP-32 mutants, indicating some specific involvement of DARPP-32 in mediating this topography of behavior; additionally, there were overall reductions in levels of sniffing, total rearing, rearing seated, and grooming in DARPP-32 mutants that were unrelated to the dose of apomorphine administered, indicating broader topographical effects following the stress of the injection procedure relative to more naturalistic conditions. The developmental absence of DARPP-32 following targeted gene deletion appears to be associated with compensatory processes that maintain certain topographies of spontaneous and agonist-induced DAergic function, while other topographies remain impaired.
authors.affiliation: Department of Clinical Pharmacology, and Institute of Biopharmaceutical Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland.
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Nally
authors.forename: Fergal N
authors.initials: FN
authors.lastname: McNamara
authors.forename: Jeremiah J
authors.initials: JJ
authors.lastname: Clifford
authors.forename: A
authors.initials: A
authors.lastname: Kinsella
authors.forename: Orna
authors.initials: O
authors.lastname: Tighe
authors.forename: David T
authors.initials: DT
authors.lastname: Croke
authors.forename: Allen A
authors.initials: AA
authors.lastname: Fienberg
authors.forename: Paul
authors.initials: P
authors.lastname: Greengard
authors.forename: John L
authors.initials: JL
authors.lastname: Waddington
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D020296:Animals, Congenic; D001058:Apomorphine / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D018491:Dopamine Agonists / Q000494:pharmacology*; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D004305:Dose-Response Relationship, Drug; D005106:Exploratory Behavior / Q000187:drug effects; D005260:Female; D006120:Grooming; D006185:Habituation, Psychophysiologic / Q000187:drug effects; D008124:Locomotion / Q000187:drug effects / Q000502:physiology; D008297:Male; D008409:Mastication; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation; D009419:Nerve Tissue Proteins; D010641:Phenotype; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D011954:Receptors, Dopamine / Q000187:drug effects / Q000378:metabolism*; D013239:Stereotyped Behavior / Q000187:drug effects; D013997:Time Factors
chemical_list: D018491:Dopamine Agonists; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D011954:Receptors, Dopamine; D001058:Apomorphine