Divergent anatomical pattern of D1 and D3 binding and dopamine- and cyclic AMP-regulated phosphoprotein of 32 kDa mRNA expression in the Roman rat strains: Implications for drug addiction.
Autoradiography analysis of D1, D2 and D3 dopamine receptors and in situ hybridization analysis of mRNA for dopamine and cAMP regulated phosphoprotein of 32 kDa (DARPP-32) were performed in brains of naïve Roman high avoidance (RHA) and Roman low avoidance (RLA) inbred rats. These strains, genetically selected for high (RHA) or extremely low (RLA) active avoidance acquisition in the two-way shuttle box, differ in indices of dopaminergic activity along with sensation/novelty and substance-seeking behavioral profiles. The present study shows no differences in D2 receptor binding between the two strains. In contrast, the D1 and D3 receptor binding in the nucleus accumbens was higher in RHA-I rats, whereas RLA-I rats show higher D3 binding in the Calleja islands. Together with previous evidence showing behavioral and presynaptic differences related to the dopamine system, the present results suggest a higher dopaminergic tone at the nucleus accumbens shell in RHA-I rats. Besides, the comparison of the expression pattern of DARPP-32 mRNA with that of dopamine receptor binding revealed a mismatch in some amygdala nuclei. In some cortical structures (prelimbic and cingulate cortices, the dentate gyrus) as well as in the central amygdala, RHA-I rats showed higher DARPP-32 mRNA expression than RLA-I rats. Hence, RHA-I and RLA-I rats may be a useful tool to identify dopamine-related mechanisms that predispose to drug and alcohol dependence.
Guitart-Masip
M
M
Medical Psychology Unit, Department of Psychiatry and Forensic Medicine, Institute of Neuroscience, Autonomous University of Barcelona, 08193 Bellaterra, Barcelona, Spain.
Johansson
B
B
Fernández-Teruel
A
A
Cañete
T
T
Tobeña
A
A
Terenius
L
L
Giménez-Llort
L
L
D000818:Animals; D001667:Binding, Competitive / Q000502:physiology; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism* / Q000494:pharmacology; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32 / Q000235:genetics*; D005106:Exploratory Behavior / Q000502:physiology; D005786:Gene Expression Regulation / Q000502:physiology; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D008032:Limbic System / Q000378:metabolism; D009714:Nucleus Accumbens / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000378:metabolism*; D017447:Receptors, Dopamine D1 / Q000378:metabolism; D050637:Receptors, Dopamine D3 / Q000378:metabolism; D013045:Species Specificity; D019966:Substance-Related Disorders / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D009435:Synaptic Transmission / Q000235:genetics
D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D012333:RNA, Messenger; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D050637:Receptors, Dopamine D3; D004298:Dopamine