Prolonged low frequency stimulation (1 Hz, 15 min) induced significant long-term depression (LTD) in hippocampal CA1 region and superficial, but not deep, layers of rat medial entorhinal cortex (EC) in vitro. In the presence of D-AP5, significant LTD was induced in EC superficial layers, but not in CA1 or EC deep layers. These results show differences in characteristics of LTD induction across CA1, EC superficial layers, and EC deep layers.