[Cellular mechanisms regulating neuronal excitability: functional implications and in epilepsy].

INTRODUCTION AND METHOD The cellular mechanisms that regulate neuronal excitability and the propagation of electrical signals in the dendrites of pyramidal neurons are incompletely understood and of key functional and pathological importance. The capacity of dendrites to actively propagate action potentials is vital in processes related to memory and learning. The deregulation of dendritic excitability may also contribute to epilepsy. The contributions of ionic conductances that regulate neuronal excitability and dendritic signal propagation have been analyzed using the in vitro hippocampal slice technique and recordings of transmembrane voltage and current of CA1 pyramidal neurons. One of these ionic currents is the slow calcium activated potassium current that generates the slow spike after hyperpolarization. CONCLUSION The dendritic localization of this current and its role in the control and propagation of electrical signals provide a key subcellular mechanisms for the control of the dendro somatic spread of synaptic signals and spike backpropagation, cellular processes closely linked with learning, memory and epilepsy.