Involvement of D2 dopaminergic receptors in the emotional and motivational responses induced by injection of CCK-8 in the posterior part of the rat nucleus accumbens.
When CCK-8 was injected in the rat posterior nucleus accumbens, where it is in part co-localized with dopamine, a decrease in exploration of the four hole box and the elevated plus maze was observed. In this study, a selective destruction of the dopaminergic mesoaccumbens pathway induced by local injection of 6-hydroxydopamine (6-OHDA) in the nucleus accumbens was found to suppress the CCK-8-evoked behavioral effects. Moreover, an ex vivo measurement of the dopaminergic metabolism has been performed after injection of CCK-8 in the posterior nucleus accumbens by electrochemical detection of dopamine and its metabolites extracted from punches of brain tissue. The results showed that CCK-8 decreased the turnover of dopamine in the posterior part but not in the anterior part of the nucleus accumbens or in the ventral tegmental area. Furthermore, sulpiride, a selective antagonist for D2 dopamine receptors, but not SCH 23390, a selective antagonist for D1 dopamine receptors, prevented CCK-8-induced behavioral responses. Taken together, these results suggest that CCK-8 could be involved in behavioral adaptation to situations producing change in emotional and/or motivational states through modulation of presynaptic D2 receptor functioning.
Derrien
M
M
Unité de Pharmacochimie Moléculaire et Structurale U266 INSERM, URA D1500 CNRS, Université René Descartes, Paris, France.
Durieux
C
C
Daugé
V
V
Roques
B P
BP
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D004298:Dopamine / Q000378:metabolism; D004644:Emotions / Q000187:drug effects*; D005106:Exploratory Behavior / Q000187:drug effects*; D006719:Homovanillic Acid / Q000378:metabolism; D007267:Injections; D008297:Male; D009042:Motivation; D009714:Nucleus Accumbens / Q000187:drug effects*; D016627:Oxidopamine; D051381:Rats; D017208:Rats, Wistar; D017448:Receptors, Dopamine D2 / Q000187:drug effects*; D012844:Sincalide / Q000008:administration & dosage* / Q000037:antagonists & inhibitors; D013681:Tegmentum Mesencephali / Q000187:drug effects / Q000378:metabolism
D017448:Receptors, Dopamine D2; D015102:3,4-Dihydroxyphenylacetic Acid; D016627:Oxidopamine; D012844:Sincalide; D004298:Dopamine; D006719:Homovanillic Acid