Neuron Article SK2 Channel Modulation Contributes to Compartment-Specific Dendritic Plasticity

Small-conductance Ca2+-activated K+ channels (SK channels) modulate excitability and curtail excit-atory postsynaptic potentials (EPSPs) in neuronal dendrites. Here, we demonstrate long-lasting plas-ticity of intrinsic excitability (IE) in dendrites that results from changes in the gain of this regulatory mechanism. Using dendritic patch-clamp recordings from rat cerebellar Purkinje cells, we find that somatic depolarization or parallel fiber (PF) burst sti-mulation induce long-term amplification of synaptic responses to climbing fiber (CF) or PF stimulation and enhance the amplitude of passively propagated sodium spikes. Dendritic plasticity is mimicked and occluded by the SK channel blocker apamin and is absent in Purkinje cells from SK2 null mice. Triple-patch recordings from two dendritic sites and the soma and confocal calcium imaging studies show that local stimulation limits dendritic plasticity to the activated compartment of the dendrite. This plas-ticity mechanism allows Purkinje cells to adjust the SK2-mediated control of dendritic excitability in an activity-dependent manner