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Corticosterone Reduces Synaptic Inhibition in Rat Hippocampal and Neocortical Neurons in vitro
Author(s) -
Zeise Marc L.,
Teschemacher A.,
Arriagada J.,
Zieglgänsberger W.
Publication year - 1992
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/j.1365-2826.1992.tb00352.x
Subject(s) - excitatory postsynaptic potential , afterhyperpolarization , neocortex , postsynaptic potential , depolarization , inhibitory postsynaptic potential , neuroscience , corticosterone , hippocampal formation , hippocampus , membrane potential , medicine , endocrinology , chemistry , biology , receptor , hormone
We examined the effect of corticosterone (10 ‐7 to 10 ‐5 M) on membrane properties and postsynaptic potentials, by means of intracellular recordings from neocortical and hippocampal CA1 pyramidal neurons of the intact adult rat in vitro . Corticosterone reduced both the early and the late components of the orthodromically‐evoked inhibitory postsynaptic potential in both structures. The glucocorticoid receptor antagonist RU 38486 (10 ‐6 M) prevented this effect in the hippocampus. In hippocampal, but not in neocortical pyramidal neurons, corticosterone reduced a depolarizing membrane transient evoked by a depolarizing current step and increased the threshold for eliciting action potentials evoked by depolarizing current pulses. Corticosterone did not detectably alter the afterhyperpolarization following repetitive neuronal discharges evoked by current injection, in either the neocortex or in the hippocampus. Excitatory postsynaptic potentials, action potentials, membrane potential and membrane input resistance were also unchanged. The decrease in synaptic inhibition together with the reduction of electrical excitability in the hippocampus, would imply a modulation of response characteristics in pyramidal neurons such that repeated synaptic inputs become more efficient and low frequency input is blunted.