| Abstrakt: |
Introduction: Recent research has provided mounting evidence that the hippocampus is not a homogenous structure but instead consists of distinct neural circuits that exhibit longitudinal variation in their anatomical and functional properties. Investigating neuronal plasticity under both normal and disease conditions, such as epilepsy, along this axis of the hippocampus, may offer critical insights into the specific neural circuits affected by seizures. Methods and Materials: In this study, we investigated the electrophysiological properties of Schaffer collateral-CA1 pyramidal neuron synapses in different dorso-ventral regions of the hippocampus. Longitudinal coordinates were used to define the position of the synapses. To assess basal transmission, we analyzed input/output curves, while short-term plasticity was measured by recording field excitatory postsynaptic potentials (fEPSPs) in response to paired-pulse stimulation at three different inter-pulse intervals (20 ms, 80 ms, and 160 ms). Long-term plasticity was evaluated using primed burst stimulation (PBS), which induced changes in synaptic strength. Results: We found that both control and PTZ-kindled rats displayed differences in basal synaptic strength between the dorsal and ventral hippocampus. Additionally, in control groups, the paired-pulse ratio (PPR) showed a systematic reduction from the dorsal to the ventral hippocampus, as well as long-term potentiation (LTP) was most pronounced in the dorsal hippocampus and decreased gradually in the intermediate and ventral regions of the hippocampus. Interestingly, PTZ-kindled rats exhibited impairments in both short-term facilitation and long-term potentiation across all three hippocampal regions, with no significant difference in synaptic plasticity between them. Conclusion: Our results suggest that seizures eliminate the regional difference between the dorsal, intermediate, and ventral parts of the hippocampus, resulting in similar electrophysiological activity in three regions in kindled animals. [ABSTRACT FROM AUTHOR] |
