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

Brain Res. 1993 Jul 23;617(2):181-8. doi: 10.1016/0006-8993(93)91084-6.


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.

MeSH terms

  • 3,4-Dihydroxyphenylacetic Acid / metabolism
  • Animals
  • Dopamine / metabolism
  • Emotions / drug effects*
  • Exploratory Behavior / drug effects*
  • Homovanillic Acid / metabolism
  • Injections
  • Male
  • Motivation*
  • Nucleus Accumbens / drug effects*
  • Oxidopamine
  • Rats
  • Rats, Wistar
  • Receptors, Dopamine D2 / drug effects*
  • Sincalide / administration & dosage*
  • Sincalide / antagonists & inhibitors
  • Tegmentum Mesencephali / drug effects
  • Tegmentum Mesencephali / metabolism


  • Receptors, Dopamine D2
  • 3,4-Dihydroxyphenylacetic Acid
  • Oxidopamine
  • Sincalide
  • Dopamine
  • Homovanillic Acid