To further evaluate the mathematical model of sparks and STOCs, we compared the voltage dependence of STOCs acquired in experiments to simulated STOCs. This is necessary and of physiological significance given that ASM cells possess a resting potential of around −40 mV, and upon stimulation under normal conditions their potential does not reach 0 mV (a potential set in the other experiments in this study to prevent STICs). To determine the voltage dependence of STOCs, we used the same paradigm as we developed for gastric smooth muscle (ZhuGe et al., 2002). In this paradigm, we set the Ek to −28 mV to facilitate the detection of STOCs at very negative potentials, and 50 µM niflumic acid was added to block STICs (Hogg et al., 1994; Janssen and Sims, 1994). Fig. 8 A (left) displays a representative set of recordings of STOCs when the cell was clamped between −100 and 20 mV. Simply considering the driving force at each potential, we can calculate the conductance underlying STOC (G(STOC)) for each event and obtain the relationship between G(STOC) and voltage (Fig. 8
