Modifications in DARPP-32 phosphorylation pattern after repeated palatable food consumption undergo rapid habituation in the nucleus accumbens shell of non-food-deprived rats.
In non-food-deprived rats a palatable meal induces a transient increase in dopamine output in the prefrontal cortex and nucleus accumbens shell and core; habituation to this response develops with a second palatable meal, selectively in the shell, unless animals are food-deprived. A palatable meal also induces time-dependent modifications in the dopamine and cAMP-regulated phosphoprotein of Mr 32 000 (DARPP-32) phosphorylation pattern that are prevented when SCH 23390, a selective dopamine D(1) receptor antagonist, is administered shortly after the meal. This study investigated whether dopaminergic habituation in the shell had a counterpart in DARPP-32 phosphorylation changes. In non-food-deprived rats, two consecutive palatable meals were followed by similar sequences of modifications in DARPP-32 phosphorylation levels in the prefrontal cortex and nucleus accumbens core, while changes after the second meal were blunted in the shell. In food-deprived rats two consecutive meals also induced similar phosphorylation changes in the shell. Finally, SCH 23390 administered shortly after the first palatable meal in non-food-deprived rats inhibited DARPP-32 phosphorylation changes in response to the first meal, and prevented the habituation to a second meal in terms of dopaminergic response and DARPP-32 phosphorylation changes. Thus, dopamine D(1) receptor stimulation plays a role in the development of habituation.
Danielli
Barbara
B
Department of Neuroscience, Pharmacology Unit, University of Siena, Siena, Italy.
Scheggi
Simona
S
Grappi
Silvia
S
Marchese
Giovanna
G
De Montis
Maria Graziella
MG
Tagliamonte
Alessandro
A
Gambarana
Carla
C
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D001552:Benzazepines / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32 / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D005508:Food Deprivation / Q000502:physiology; D005518:Food Preferences / Q000187:drug effects / Q000502:physiology*; D006185:Habituation, Psychophysiologic / Q000502:physiology*; D008297:Male; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012457:Salicylamides / Q000494:pharmacology; D013549:Sweetening Agents / Q000008:administration & dosage; D013912:Threonine / Q000378:metabolism; D013997:Time Factors
D001552:Benzazepines; D018492:Dopamine Antagonists; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; C497930:Ppp1r1b protein, rat; C534628:SCH 23390; D012457:Salicylamides; D013549:Sweetening Agents; D013912:Threonine; C045989:eticlopride