Hydrogen peroxide regulates metaplasticity in the hippocampus

Abstract

The brain ties a thread between temporally distinct events through the use of memory. The biological substrate of memory, the memory "trace" or the "engram" has been extensively searched for over the past century and much of what we know about the cellular and molecular machinery of memory comes from studies conducted on the hippocampus. The Schaffer collateral synapse in region CAI which can be potentiated by a train of vulses has been most instrumental in demonstrating the different phases of - memory formation and the mechanisms that control them. In their seminal paper, Stanton and Sarvey (1984), demonstrated the need for protein synthesis in the expression of hippocampal long term potentiation (LTP). They also showed that short term potentiation did not require new protein synthesis. These findings offered a molecular basis for behavioral phenomena described earlier, namely, that memory itself can be divided into temporally distinct phases. In the present chapter we will discuss the results of a series of experiments that were also triggered by a seminal work of John Sarvey (Pellmar et al. 1991). We describe how the ability to produce LTP is controlled by different concentrations of hydrogen peroxide (H202), a phenomena of meta-plasticity that is altered throughout the life of the organism and may control the ability of some brain circuits to remember.