title: Consolidation of object recognition memory requires simultaneous activation of dopamine D1/D5 receptors in the amygdala and medial prefrontal cortex but not in the hippocampus.
abstract: The mesocorticolimbic dopaminergic system includes the ventral tegmental area (VTA) and its projections to the amygdala (AMY), the hippocampus (HIP) and the medial prefrontal cortex (mPFC), among others. Object recognition (OR) long-term memory (LTM) processing requires dopaminergic activity but, although some of the brain regions mentioned above are necessary for OR LTM consolidation, their possible dopamine-mediated interplay remains to be analyzed. Using adult male Wistar rats, we found that posttraining microinjection of the dopamine D1/D5 receptor antagonist SCH23390 in mPFC or AMY, but not in HIP, impaired OR LTM. The dopamine D2 receptor agonist quinpirole had no effect on retention. VTA inactivation also hindered OR LTM, and even though this effect was unaffected by co-infusion of the dopamine D1/D5 receptor agonist SKF38393 in HIP, mPFC or AMY alone, it was reversed by simultaneous activation of D1/D5 receptors in the last two regions. Our results demonstrate that the mesocorticolimbic dopaminergic system is indeed essential for OR LTM consolidation and suggest that the role played by some of its components during this process is much more complex than previously thought.
authors.affiliation: Memory Research Laboratory, Brain Institute (ICe), Federal University of Rio Grande do Norte (UFRN), Natal, RN 59056-450, Brazil; Laboratory of Behavioral Neurobiology, Biomedical Research Institute, Porto Alegre, RS 90610-000, Brazil.
authors.forename: Janine I
authors.initials: JI
authors.lastname: Rossato
authors.forename: Andressa
authors.initials: A
authors.lastname: Radiske
authors.forename: Cristiano A
authors.initials: CA
authors.lastname: Kohler
authors.forename: Carolina
authors.initials: C
authors.lastname: Gonzalez
authors.forename: Lia R
authors.initials: LR
authors.lastname: Bevilaqua
authors.forename: Jorge H
authors.initials: JH
authors.lastname: Medina
authors.forename: Martín
authors.initials: M
authors.lastname: Cammarota
mesh_terms: D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000679:Amygdala / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D017397:Prefrontal Cortex / Q000187:drug effects* / Q000378:metabolism; D019257:Quinpirole / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000819:agonists; D050641:Receptors, Dopamine D5 / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D001552:Benzazepines; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C534628:SCH 23390; D050641:Receptors, Dopamine D5; D019257:Quinpirole; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine
keywords: Amygdala; Dopamine; Hippocampus; Medial prefrontal cortex; Object recognition memory; Ventral tegmental area