Figure 1.

Functional BK_Ca or K_ir channels are not present in freshly isolated aortic endothelial cells. (Aa) Typical family of traces recorded from freshly isolated aortic endothelial cells dialyzed with a pipette solution containing 1 mM Mg²⁺ and 3 μM Ca²⁺ before (Control) or following application of 100 nM IbTX. From a holding potential of −50 mV, currents were evoked by 100-ms voltage steps from −100 to +100 mV in a 10-mV increment followed by a 100-ms repolarizing step to −50 mV. (Ab) Mean IbTX-sensitive current recorded from four experiments similar to the one shown in Aa. (B) Mean ramp currents in the absence (Control, black trace) and presence (Barium, red trace) of 0.5 mM barium (n = 5). These currents were elicited using 45 mM extracellular K⁺ to emphasize potential K_ir currents. Currents were induced by a 200-ms voltage ramp protocol from −100 mV to +100 mV (HP = −60 mV).