OBJECTIVETo study potassium currents in isolated Deiters' cells of guinea pig cochlea and explore possible function of potassium current in Deiters' cell.

METHODSThe whole cell patch clamp recording technique was used to study potassium currents of Deiters' cells in normal external solution and solutions with different K(+) concentrations. We also studied the effects on reversal potentials and outward potassium currents.

RESULTSIsolated Deiters' cells possess voltage dependent, outwardly rectifying ion channels, which are K(+) selective. 50 mmol/L K(+) and 150 mmol/L K(+) in external solution reduced I(K-max) from (10.06 +/- 2.2) nA (n = 13) in normal external solution to (6.43 +/- 1.67) nA (n = 6, P < 0.05) and (5.49 +/- 1.33) nA (n = 6, P < 0.05), respectively. While the amplitude of tailcurrents decreased from (468.76 +/- 61.76) pA in 5 mmol K(+) external solution to (224.74 +/- 35.89) pA (P < 0.05) in 50 mmol/L K(+) and to (-911.59 +/- 78.17) pA (P < 0.01) in 150 mmol/L K(+) external solution.

CONCLUSIONSOutwardly rectifying potassium in Deiters' cells could buffer extracellular K(+) in the small space between Deiters' cells and outer hair cells or neural fibers and participate in the diffusion of K(+) from endolymph to perilymph.