The effect of D2 dopaminergic system in nucleus accumbens and glutamatergic system of prelimbic area on anxiety- like behaviors in Wistar male rats.

Background: Neutrustransmitter systems of dopaminergic and glutamatergic of the prefrontal cortex (PFC) and nucleus accumbens (NAc) are involved in the regulation of anxiety-like behaviors. In addition, the activity of the NAc dopaminergic system is mediated by the glutamatergic inputs, which is mainly from the PFC. This study investigated the role of D2 dopaminergic system in nucleus accumbens and glutamatergical system of prelimbic area on anxiety- like behaviors in male rats.

Methods: This study was performed on four experimental groups in 35 groups of 8 male rats. after 5 days of surgery in a stereotaxic frame, the Elevated Plus maze apparatus was employed for the recording parameters of anxiety-like behaviors due to intr-abrain injection of quinpirole (Dopamine receptor agonist), sulpiride (Dopaminergic D2 receptor antagonist), NMDA(NMDA receptor agonist) and D-AP7 (NMDA receptor antagonist.

Results: Unilateral intra- left prelimbic injection of NMDA (0.9 μg/μl) reduced the anxiety-like behaviors (P<0.01), which was blocked by D-AP7 injection (P<0.01). Also, unilateral infusion of sulpiride (0.4 and 0.6 μg/μl) into the NAc shell induced anxiolytic-like behaviors (P<0.05). Furthermore, the administration of the sub threshold dose of sulpiride (0.2 μg/μl) in the NAc shell strengthened the effect of low dose NMDA (P<0.05), whereas reduced its high dose (P<0.01) in prelimbic.

Conclusion: The results indicate the regulatory effect of the dopamine D2 system of NAc shell on the anxiolytic-like response caused by NMDA injection in prelimbic region.