Roles of ion channels in EPSP integration at neuronal dendrites.

Many different kinds of voltage-gated ion channels (Na+ channels, K+ channels, Ca2+ channels) exist at neuronal dendrites. Integration of dendritic electric signals (excitatory postsynaptic potentials (EPSPs), inhibitory postsynaptic potentials (IPSPs) and action potentials) and/or non-electric signals (Ca2+ and second messengers) occurs in restricted dendritic compartments consisting of spines and adjacent fine dendrites. Voltage-gated ion channels at neuronal dendrites play crucial roles in the integration of dendritic signals. Dendritic signals, in turn, play important roles in the modulation of local dendritic physiological functions (e.g. input-specific synaptic plasticity, long-term potentiation (LTP) and long term depression (LTD)). A combined experimental and theoretical approach is a good way to clarify the biophysical behaviors of dendritic ion channels. Analyses of dendritic ion channels can open the door to a new wave of discoveries about EPSP integration at neuronal dendrites.