Requirement of hippocampal phospholipase A2 activity for long-term memory retrieval in rats

In rats, the inhibition of phospholipase A2 (PLA2) in hippocampus was reported to impair memory acquisition. In the present study we investigated in rats whether PLA2 inhibition in hippocampus is also related to impairment of memory retrieval. Rats were bilaterally implanted with cannulae in hippocampal CA1 region. After recovery, animals were submitted to one-trial step-down inhibitory avoidance task and tested for long-term memory (LTM) 24 h later. Before test session, animals received infusions of vehicle or the PLA2 inhibitor PACOCF3. Inhibition of PLA2 activity impaired LTM retrieval. Memory impairment was fully reversed once PLA2 activity was recovered. Moreover, LTM retrieval per se increased PLA2 activity. To our knowledge, we demonstrated for the first time that PLA2 activity is required for memory retrieval. Because reduced PLA2 activity has been found in Alzheimer’s disease brains, the present results may be relevant to clarify at least part of the biology of this disorder.