Figure 6

Inwardly rectifying K⁺ currents after three days in proliferation medium and further six days in differentiation medium. (A) Original voltage clamp recordings of current traces from cell cultured after 9 days in control solution. No leak and capacitance subtraction used to visualize current components at a holding potential of -85 mV. (Aa) Current traces in physiological extracellular solution, (Ab) in the same solution containing in addition 1 mM Ba²⁺. (Ac) plot of the difference between traces shown in (Aa) and (Ab) corresponding to the inwardly rectifying K⁺ current (K_IR). (B) Current versus voltage relationship for recordings shown in Ac (mean current between the dashed lines in Ac). (C) Fraction of cells showing a K_IR current larger than 50 pA for each tested culture condition. The number of cells tested under each condition (control: C, pretreatment with TNF-α and IFN-γ for 48 hours:TI, control cultures treated with dexamethasone: CD, cultures co-treated with dexamethasone and TNF-α and IFN-γ for 48 hours: TID) is indicated within the corresponding column. (D) Average current densities of K_IR for the cells listed positive for this current in (C). Note, that after 3 days in proliferation medium containing TNF-α and IFN-γ for 48 hrs the number of cells showing a K_IR was reduced to only 20%. Error bars indicate ± SE.