Homeostatic regulation of h‐conductance controls intrinsic excitability and stabilizes the threshold for synaptic modification in CA1 neurons

摘要

Key points class="unordered" style="list-style-type:disc" id="tjp6826-list-0001">We determined the contribution of the hyperpolarization‐activated cationic (h) current (I h) to the homeostatic regulation of CA1 pyramidal cells in vitro using chronic treatments (48 h) that either increase (picrotoxin) or decrease (kynurenate) neuronal activity.The h‐conductance was found to be up‐ or down‐regulated following chronic activity enhancement or activity deprivation, respectively. This bidirectional plasticity of I h was found to subsequently alter both apparent input resistance and intrinsic neuronal excitability.Bidirectional homeostatic plasticity of I h also determined EPSP waveform and EPSP summation tested at 5–30 Hz.Long‐term synaptic modification induced by repetitive stimulation of the Schaffer collaterals was found to be constant across treatments in the presence of I h but not when I h was blocked pharmacologically. Thus, bidirectional homeostatic regulation of I h stabilizes induction of long‐term synaptic modification in CA1 pyramidal neurons that depends on EPSP summation.