Abstract
Long-term potentiation (LTP) of excitatory postsynaptic potentials (epsp's) was investigated with extracellular field potential recording in hippocampal slices from rats. In the presence of 100 microM 4-aminopyridine (4-AP) the probability of eliciting LTP was unchanged or increased; the extent of potentiation was not significantly different from normal. During LTP saturation, 4-AP further enhanced the epsp. These data are inconsistent with an involvement of A-current reduction in LTP.