Figure 3.

Effect of A-251179 on membrane current and potential in guinea-pig bladder smooth muscle cells. (a) Application of 10 μM A-251179 evoked an increase in inward whole-cell current in guinea-pig bladder smooth muscle cells that was sensitive to the inhibition by 5 μM glyburide. Cells were voltage-clamped at −80 mV and changes in membrane currents were measured in bath solution containing 60 mM K⁺ with pipette solution containing 140 mM K⁺ and 0.1 mM ATP. (b) A-251179 also lowered membrane potential in bladder smooth muscle cells. In the trace shown above, 10 μM A-251179 hyperpolarized membrane potential, which was reversed to control values in the presence of 5 μM glyburide. The K⁺ equilibrium potential is −20 mV under the current-clamp recording conditions where the intracellular and extracellular K⁺ concentrations are 140 and 60 mM, respectively.