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.

Dopamine dysregulation in the prefrontal cortex relates to cognitive deficits in the sub-chronic PCP-model for schizophrenia: A preliminary investigation

“…We have also established that SKF-38393, when given systemically, can reverse the scPCP-induced deficit in NOR in female rats (McLean et al, 2009). This is supported by data reporting that microinfusion of the dopamine D 1 -like receptor antagonist SCH-23390 into the rat mPFC produced a deficit in NOR (Rossato et al, 2013;Clausen et al, 2011).…”

Role of the anterior cingulate cortex in the retrieval of novel object recognition memory after a long delay

“…This suggests that, following the 24 h delay information underlying NOR retrieval was present in the ACgx, which, in line with the findings reviewed above, shows that the NOR information may have been consolidated into the ACgx. As mentioned above, one function of the mPFC is to consolidate NOR memory, and the role of dopamine in the consolidation of long-term memory has recently been investigated by Rossato et al (2013). They infused the D1 receptor antagonist SCH13390 into the mPFC just after the encoding of a NOR task and found that such a manipulation affected consolidation.…”

From attention to memory along the dorsal-ventral axis of the medial prefrontal cortex: some methodological considerations

“…Although lesion methods suggest that mPFC is not necessary for object recognition as measured by the standard test variant based on object identity (Ennaceur et al, 1997; Hannesson et al, 2004a; Nelson et al, 2011a), this does not exclude a modulatory role for mPFC. Indeed, evidence that the role of DA D 1 -like receptors in the consolidation of novel object recognition memory (de Lima et al, 2011) is mediated in mPFC has been provided by evidence for DA D 1 regulation of protein synthesis after novel object exposure (Nagai et al, 2007) as well by micro-injection experiments comparing the effects of DA D 1 –like receptor agents with DA D 2 receptor agents in mPFC (Nagai et al, 2007; Rossato et al, 2013). Similarly, we have recently found that novel object recognition is impaired by the DA D 1 agonist SKF81297, both after systemic injections and after microinfusion directly into PL mPFC (Pezze et al, unpublished data).…”