LTP and PKM zeta in perirhinal cortex

Long-term potentiation (LTP) is thought to underlie learning and memory processes. Protein Kinase M Zeta, the independently active PKC Zeta isoform, is both necessary and sufficient for the maintenance of the late-phase of LTP in the hippocampus and for the long-term storage of spatial information in behavioural tests (Pastalkova et al., 2006). However, little is known about the mechanisms underlying the maintenance of LTP in perirhinal cortex, a cortical region critical for recognition memory. We demonstrate that a ÒspacedÓ tetra-burst stimulation (four 100-Hz bursts at 5-min interburst interval) in perirhinal cortex is able to induce an LTP lasting longer than 5 hours, which is sensitive to protein synthesis inhibitors. The crucial role of PKM Zeta is confirmed by the reversal of LTP maintenance following the application of the peptide inhibitor ZIP. We are currently studying the role of PKM Zeta in depotentiation and investigating mechanisms involved in modifying the synthesis and/or the activation of this Kinase. Pastalkova E et al. (2006) Storage of spatial information by the maintenance mechanism of LTP. Science 313:1141-4.