Imaging of gene expression during long-term potentiation.

Long term potentiation (LTP) at hippocampal Schaffer collateral-CA1 synapses involves an early and a late phase, where only the latter is sensitive to protein synthesis inhibitors. Here we characterized the dynamics of protein synthesis associated with the induction of L-LTP using a transgenic mouse model in which a cAMP responsive element (CRE)-regulated promoter drives production of an enhanced yellow fluorescent protein (eYFP). We found that eYFP fluorescence increased after less than 30 min following L-LTP induction. Application of transcription and translation suppressors and the NMDA receptor antagonist D-AP5 inhibited the L-LTP and prevented the rise in eYFP levels. The early-phase of LTP was not affected by inhibiting protein synthesis.