Mammalian 2P domain K(+) channels are responsible for background or 'leak' K(+) currents. These channels are regulated by various physical and chemical stimuli, including membrane stretch, temperature, acidosis, lipids and inhalational anaesthetics. Furthermore, channel activity is tightly controlled by membrane receptor stimulation and second messenger phosphorylation pathways. Several members of this novel family of K(+) channels are highly expressed in the central and peripheral nervous systems in which they are proposed to play an important physiological role. The pharmacological modulation of this novel class of ion channels could be of interest for both general anaesthesia and ischaemic neuroprotection.