The inward rectifier potassium conductance in rat basophilic leukemia cells

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Abstract
Whole-cell recordings were made from rat basophilic leukemia cells. The properties of the cells in the potential range negative to −20 mV could be accounted for by two potassium conductances, a leakage conductance (0.54 ± 0.01 nS, mean ± s.e.m., n − 6) and an inward rectifier conductance. The inward rectifier conductance activated at a potential close to Ek and had a maximal value of 2.7 ± 0.22 nS (n = 6 ). Cesium (2 mM, n = 6) decreased the inward current at every potential. Strontium (10 mM, n = 7) and rubidium (2 mM, n = 3) had a similar effect, but they also increased the slope conductance between −63 and − 103 mV. Barium (1–100 pM) blocked selectively the inward rectifying current without affecting the leakage current; the effect was use-, voltage-, and temperature-dependent. TEA decreased the current; the concentration giving 50% inhibition was 37.5 mM. The current was unaffected by phorbol esters as well as several hormones and transmitters that werg tested.