Development of synaptic responses and plasticity at the SC-CA1 and MF-CA3 synapses in rat hippocampus

The development of synaptic transmission and indicators of short- and long-term plasticity was studied by recording from areas CA1 and CA3 upon activation of monosynaptic excitatory inputs in rat hippocampal brain slices obtained from Wistar rats of different ages. Although population field excitatory postsynaptic potentials (fEPSPS) are small in animals at postnatal day 10 (P10), both areas already exhibited short-term [posttetanic potentiation (PTP) and paired pulse potentiation (PPF)] and long-term [long-term potentiation (LTP)] plastic responses. The amplitudes of the fEPSP and LTP increased with age in both regions, but peaked at P30 in CA3 while they were still increasing at the oldest age studied (P60) in CA1. In CA3, but not CA1, LTP at P60 was less than at P30. PTP did not show clear alterations with age in either region. PPF decreased with age in CA1 but not CA3.