PKMζ contributes in consolidation, retrieval and maintenance of amygdala dependent fear memory in rats

Introduction: Protein kinase M zeta (PKMζ) is assumed to be actively involved in retainig long-term potentiation. The goal of this study was to investigate the role of PKMζ in basolateral amygdala (BLA) upon acquisition, consolidation, retention and retrieval of memory using a specific inhibitor of PKMζ. Methods: Sixty male wistar rats underwent stereotaxic surgery and were cannulated bilaterally at the BLA nucleus. Then animals were divided into 4 groups of receiving BLA microinjection of zeta inhibitory peptide (ZIP) in different time courses: 30 min before and after training, 30 min before the testing (on the day after the learning) and 30 min after testing (but testing 10 days later). Memory was assessed using step through passive avoidance. Results: ZIP infusion in BLA had no significant change on acquisition (P=0.06), however significantly impaired consolidation, retrieval and maintenance of passive avoidance memory (P=0.012). Conclusion: Findings indicate that PKMζ activity in the BLA plays an important role in retaining amygdala dependent avoidance memory interfering the process of consolidation, retrieval and maintenance of learned task.