Figure 4: BM-derived SMCs show two types of K+ channel currents. The graph represents I-V curves for the BM-derived SMCs and bulk-stromal cells. Ten mV-increment depolarizing voltage steps were applied from a holding potential of -80 mV to +80 mV. In BMSC-derived SMCs, switching from control solution (1.8 mM Ca2+, ●) to Ca2+-free solution (○) decreased K+ channel currents, indicating at least two types of K+ channels present: decreased K+ current (KCa current) and resting K+ current (KV current). The bulk-stromal cells showed KV current, but not KCa current.