Van Harreveld A
Neurosci Lett. 1984 Sep 7;50(1-3):283-7. doi: 10.1016/0304-3940(84)90500-7.
In addition to promoting long-lasting negative (and positive) dendritic field potentials elicited by stimulation of Schaffer collaterals in hippocampal slices, 4-aminopyridine causes a slow negative wave which may have another origin than the dendritic potentials.