Presynaptic potassium channels.

The past year has witnessed some significant improvements in our understanding of the molecular diversity, subunit composition, and functional properties of K+ channels in heterologous expression systems. Immunocytochemical studies have yielded important information on the localization of K+ channel proteins to synaptic terminals in mammalian brain. Although a coherent picture of native presynaptic K+ channels' function in the mammalian central nervous system is not yet available, it may emerge from improvements in patch-clamp techniques and new applications of targeted knock-out technologies.