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Age‐related Changes in Excitability and Recurrent Inhibition in the Rat CA1 Hippocampal Region
Author(s) -
Papatheodoropoulos Costas,
Kostopoulos George
Publication year - 1996
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1996.tb01235.x
Subject(s) - excitatory postsynaptic potential , neuroscience , senescence , population spike , electrophysiology , population , stimulation , postsynaptic potential , hippocampal formation , biology , inhibitory postsynaptic potential , medicine , receptor , environmental health
Abstract In hippocampal slices from male Wistar rats aged 1–34 months, we recorded the synaptic field potential responses of the CA1 neurons to stimulation of Schaffer collaterals. Eight electrophysiological indexes were extracted from input/output curves and compared in 11 age groups from 1 to 30 months. Neuronal excitability presented a U‐shaped curve of development with a minimum at ˜7–8 months of age. There was a significant continuous increase in neuronal excitability, i.e. a decrease in excitatory postsynaptic potential (EPSP) producing both the threshold and half‐maximal population spike from middle age (8–10 months) to senescence (30 months). Synaptic efficiency also increased in old rats to reach a maximum during senescence, i.e. both the current for threshold EPSP and that for half‐maximal EPSP reached a minimum in senescence, although the earlier developmental patterns of these two indexes were non‐linear. The duration of the field EPSP elicited with maximal stimulation presented an abrupt decay after the first month. Aged animals presented a relatively small maximal population spike. Recurrent inhibition was most prominent on neuronal excitability rather than synaptic strength. Measured as the percentage change in the half‐maximal EPSP and half‐maximal population spike, recurrent inhibition was found to decrease during the first 7–10 months of life and remained small in later development.