Interaction between Effects of Opioidergic System of Prefrontal Cortex and Dopaminergic System of Basolateral Amygdala in Working Memory

Abstract

Background and Aim: Working memory is a dynamic neural system for temporarily maintaining and processing of information. Prefrontal cortex (PFC) is the main processing center of Working memory by using different neurotransmitter systems communicate with other brain structures such as Basolateral Amygdala (BLA). In this study, we investigated the role of Opioidergic system in medial PFC and Dopaminergic system of BLA nucleus in working memory based on RAM test. Materials and Methods: In this study, The male Wistar rats were used. Rats were cannulated with stereotaxic surgery in mPFC and BLA sites. After a recovery period, they were microinjected. Parameters such as working and reference memory errors were calculated with DSWS protocol. Ethical Considerations: This study with research ethics code IR.UMZ.REC.1397.23 has been approved by Bioethics Committee at Mazandaran University, Iran. Findings: High doses of Morphine (2 µg/rat) intra mPFC and Chloropromazine (2 µg/rat) intra BLA have improving effects on working and reference memory (p≤0.05). Low (0.005 µg/rat) and high dose (0.5 µg/rat) of Apomorphine had improving {(p≤0.05), (p≤0.01)} and the moderate dose (0.05 µg/rat) of it had decreasing effect on working and reference memory (p≤0.01). Microinjection of Morphine (0.5 µg/rat) with triple doses of Chloropromazine had no significant change on working and reference memory errors. Interaction of Morphine (0.5 µg/rat) with different doses of Apomorphine could change Apomorphine different effects. Coadministration of different doses of Apomorphine with effective dose of Chloropromazine (2 µg/rat) and Morphine (2 µg/rat) decreased the working and reference memory errors. Conclusion: Our findings showed that in processing of working and reference memory, opioidergic system in mPFC and dopaminergic system in BLA, are interacting reciprocally.

Keywords

• Apomorphine
• Basolateral Amygdala
• Chloropromazine
• Morphine
• Prefrontal cortex
• Working memory