Voltage dependence of Ip. Representative Ip recordings obtained at different holding potentials from −90 to −30 mV, for a change from 0 K-EXT to 10 K-EXT solution. The approximate duration of the exposures to 10 mM K⁺ is indicated above the current records. The holding potential between two consecutive levels was changed slowly over a period of ∼10 s. The schematic at the top of the panel indicates the imposed holding potentials, not the transitions between them. An additional period of 60–90 s was allowed before the [K⁺] change was imposed. Individual Ip records are arbitrarily placed near each other. Temperature, 23°C.