Long-lasting potentiation of the dentate gyrus population spike by norepinephrine.

The effects of iontophoretically applied norepinephrine (NE) on the dentate gyrus field potential evoked by perforant path stimulation were examined. NE potentiated the population spike by 20-400%, whereas the population EPSP was rarely increased. At 39% of the potentiated sites NE application resulted in long-lasting potentiation (LLP) suggesting a role for NE in long-term hippocampal plasticity.