Analysis of conditions that are important for the beginning of consolidation in a model of long-term synaptic potentiation

Abstract

Long-term potentiation (LTP) is one of the most studied forms of long-term plasticity. Irreversible final modifications are a specific feature of the late phase of LTP. However, the initial modifications may disappear spontaneously or under conditions of less intense tetanization or the influence of depotentiating factors. The protein-dependent consolidation process, which mainly occurs within the first 30 min after induction in the LTP model, is an important condition for the maintenance of long-term modifications. In this article, the data that support the importance of local protein synthesis in the synaptic compartments are reviewed and the main principles of the regulation of the expression of genes that are crucial for consolidation are presented. We also discuss the role of directed mRNA transportation to the respective dendritic compartments and the involvement of reinforcing factors that are capable of eliciting and enhancing consolidation-related modifications. Taking the functional importance of transcription products into account, we can conclude that the key processes of consolidation are associated with the rearrangement of cytoskeletal proteins. This rearrangement is important for both the compartmentalization of proteins that are synthesized de novo and structural modifications found in LTP. Some factors indicate the similarity of the molecular mechanisms of consolidation in the pre- and postsynaptic compartments. Key proteins and enzymes of LTP consolidation are also involved in learning and memory; therefore, the principles that are discovered in models of long-term plasticity may be used for future experiments on animal learning in order to find similar mechanisms that are too local and diffuse, which makes their direct observation very difficult.