Individual differences in schedule-induced polydipsia: neuroanatomical dopamine divergences.
Autoradiography analysis of D1 and D2 dopamine receptors and c-Fos activity were performed in brain of rats classified as low drinkers (LD) and high drinkers (HD) according to schedule-induced polydipsia (SIP) performance. Previous studies have shown that groups selected according to their rate of drinking in SIP differ in behavioral response to dopaminergic drugs. This study reports differences between LD and HD rats in dopamine D1 and D2 receptor binding through different mesocorticolimbic brain areas. LD and HD rats showed opposite patterns of binding in dopamine D1 and D2 receptors in the nucleus accumbens, medial prefrontal cortex, amygdala, ventral tegmental area and substantia nigra. Whereas LD rats showed higher binding than HD rats for D1 receptors, HD rats showed higher binding than LD rats for D2 receptors (except in substantia nigra that were roughly similar). These neuroanatomical differences in dopamine receptor binding were also associated with an elevated c-Fos count in the medial prefrontal cortex of HD rats. In tandem with previous evidence, our results suggest a different dopaminergic function between LD and HD, and points to SIP as a behavioral model for distinguishing populations possibly vulnerable to dopaminergic function disorders.
Laboratorios de Conducta Animal y Neuroquímica, Facultad de Psicología, Universidad Nacional de Educación a Distancia, C/ Juan del Rosal 10, Ciudad Universitaria, 28040 Madrid, Spain. rpellon@psi.uned.es
Ricardo
R
Pellón
Ana
A
Ruíz
Margarita
M
Moreno
Francisco
F
Claro
Emilio
E
Ambrosio
Pilar
P
Flores
D000679:Amygdala / Q000378:metabolism; D000818:Animals; D004327:Drinking Behavior; D007206:Individuality; D008297:Male; D009474:Neurons / Q000378:metabolism*; D009714:Nucleus Accumbens / Q000378:metabolism; D017397:Prefrontal Cortex / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D012055:Reinforcement Schedule; D013378:Substantia Nigra / Q000378:metabolism; D017557:Ventral Tegmental Area / Q000378:metabolism
D016760:Proto-Oncogene Proteins c-fos; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2