Translational suppression of calpain blocks long-term potentiation.

Transfection with antisense oligonucleotides was used to reduce calpain 1 activity to approximately 50% of normal values in cultured hippocampal slices. This had no detectable effects on baseline synaptic responses but greatly reduced the incidence and magnitude of long-term potentiation induced with a theta-burst stimulation paradigm. These results suggest that activation of calpain by repetitive bursts of afferent activity, as shown to occur in prior studies, is an essential step in the production of stable increases in synaptic strength.