Figure 4.

The single-channel currents activated by loperamide are insensitive to tolbutamide. Single-channel currents were measured in the cell-attached configuration under control conditions with 2.5 mM Ca²⁺ (panel a) after 3 min exposure to 30 μM loperamide (LPM) in ‘0' Ca²⁺ solution (panel b), and after 100 μM of the specific K_ATP channel blocker tolbutamide had been added to the loperamide-containing, but Ca²⁺-free solution (panel c). The records are representative of three similar experiments conducted in different cells. The glucose concentration was 5.6 mM.