Figure 3 .

Effect of 1 µM ethylisopropylamiloride (EIPA) on large conductance K⁺ channels in isolated surface cells from rat distal colon. Typical recording from a cell attached patch of membrane from a distal colonic surface cell isolated from K⁺ loaded animal (Na₂SO₄ solution in bath, K₂SO₄ solution in the pipette; V_com = 0 mV). (A) K⁺ channel activity on slow time base before and after the addition of 1 µM EIPA to the bath (denoted by arrow). Sections of (A) are presented on a faster time base to compare K⁺ channel activity before the addition of EIPA (B) and afterwards (C). (D) Restoration of channel activity after removal of EIPA. The dashed lines indicate zero current levels, and downward deflections indicate K⁺ flow from the pipette to the cell.