Decreased ability of rat temporal hippocampal CA1 region to produce long-term potentiation

Tetanic stimulation of Schaffer collaterals in the CA1 region of transverse slices, taken from the septal (dorsal) part of young rat hippocampus, prod uced N-Methyl-D-aspartate-dependent long-term potentiation (LTP) of the ris ing slope of excitatory postsynaptic potential (mean 38%). Under identical conditions of stimulation (100 Hz, 1 s) slices taken from the temporal (ven tral) third of hippocampus presented a substantially reduced ability for LT P (mean 5%). The defect appeared to lie with the induction rather than the maintenance phase of LTP. These results suggest that a significant function al differentiation at the local synaptic plasticity level occurs between th e two poles of hippocampus, which together with the substantial differences in their extrinsic connections, may help explain the reported differential participation of neutrons in these parts of hippocampus during animal memo ry tests. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.