Figure 4. Families of voltage-gated ion channels expressed in control BM-hMSCs.

(A–C) Representative traces of voltage-activated outward currents, identified as K⁺ currents. Channels were stimulated by applying 300 ms long depolarizing steps from −90 to +80 mV in 10 mV increments, starting from a V_hold (holding potential) of −90 mV. The corresponding current-voltage relationship (I–V) is reported to the side of each series of traces. (D,E) Traces of voltage-gated inward currents recorded in control BM-hMSCs. (D) Transient inward currents were elicited in standard ionic conditions. Steady-state activation parameters were calculated assuming a reversal potential of +90 mV and fitted to a Boltzmann equation (equation [1]). In this cell V_1/2 = −30.9 mV and =11.26. Similar results were found for the other cells. (E) A slower, more persistent inward current was elicited by applying 100 ms long pulses in Na⁺-free conditions and in the presence of Ba²⁺ only as charge carrier. Boltzmann parameters of Ca²⁺ currents are reported and explained in the text.