Figure 4. Pharmacological properties of K_ATP channels with 75 pS conductance in Ca²⁺-free pipette solution.

Drugs were applied at the beginning of each recording and representative traces are shown at the times indicated. The dotted lines indicate the closed level and dashed lines indicate the open levels. A, time course of diazoxide action. Patch holding potential, 0 mV. B and C, two representative experiments of K_ATP channel inhibition in inside-out patches by tolbutamide (B) and glibenclamide (C) at holding potentials of -25 and -40 mV, respectively. The data shown in B and C were obtained in patches that had not been subjected to any prior treatment.