It was recently discovered that two different types of voltage-insensitive K+ channels, G protein-coupled inwardly rectifying K+ (GIRK) and small-conductance Ca2+-activated K+ (SK) channels, are located on dendritic branches, spines and shafts in the postsynaptic densities of excitatory synapses in many central neurons. Together with increases in our knowledge of how these channels are regulated through stable protein-protein interactions in multi-protein complexes, this has added another layer of complexity to our understanding of synaptic transmission and plasticity.