Single Channel Seeks Permeant Ion for Brief but Intimate Relationship

Ion channels don't like having their permeant ions taken away. Particularly when they are in the mood to let ions through, this sort of deprivation makes them feel downright unstable. Like jilted lovers, they shut the door and become listless, inactive(-ated), and sometimes even immobilized. Channel physiologists have long tried to ignore this dejected behavior on the part of the channels, even though for many years it has been clear that channels often refuse to gate normally in unfriendly ionic conditions. The best known such effect is the slowed closing of channels in the presence of high concentrations of certain permeant ions, often called the “foot in the door” effect (Yeh and Armstrong, 1978). This type of effect was first noticed for synaptic channels (Ascher et al., 1978; Marchais and Marty, 1979) and has been studied in detail for a variety of K^+...