view:27619 Last Update: 2021-9-5
Mohaddeseh Ebrahimi-Ghiri, Mohammad Nasehi, Mohammad-Reza Zarrindast
Simultaneous injection of sulpiride into the hippocampus and nucleus accumbens increases open-arms exploratory behavior in the EPM test-retest protocol
تزریق همزمان سولپیراید به درون هیپوکامپ و هسته آکومبنس رفتار جستجوگرانه بازوی باز در پروتوکل EPM test-retest را افزایش می دهد
Introduction: The hippocampus and nucleus accumbens dopaminergic (DAergic) system has been implicated in cognitive functions such as anxiety, learning and memory. To clarify the interaction between dorsal hippocampal (DH) and nucleus accumbens (NAc) DAergic system in the acquisition of anxiety-like behavior and aversive learning, the effect of sulpiride, as a DAergic D2-like receptor antagonist, and co-injection of this drug into these structures were studied on the acquisition of anxiety-like behavior and aversive learning using an elevated plus-maze (EPM) test-retest paradigm in the male Wistar rats. Materials and methods: Unilateral guide cannulae were implanted to allow microinjection of sulpiride. Results: Pretest microinjection of sulpiride (0.125-0.5µg/rat) into the NAc increased the percentage of time spent in open-arms (%OAT), suggesting anxiolytic-like response. However, the control group rats displayed experience-induced increases in open-arm avoidance when retested in the EPM, suggesting the storing of aversive information about the maze was preserved. In contrast, sulpiride-treated rats failed further avoidance to open-arms, indicating aversive learning deficit. Moreover, pretest microinjection of sulpiride (0.25-1 µg/rat) into the DH produced no anxiety- or anxiolytic-like effect but impaired aversive learning. Furthermore, subthreshold dose of sulpiride into both sites induced anxiolytic-like effect and aversive learning deficit. Conclusion: Our data suggest involvement of D2 receptors in dopaminergic system interaction between DH and NAc regulating anxiety-related behaviors and EPM associative memory.