Figure 4
Wortmannin does not inhibit BVT.12777 activation of K ATP A, current clamp record of a CRI-G1 cell dialysed with 5 mM MgATP, following exposure of cells to 10 nM wortmannin for 15–20 minutes. Application of BVT.12777 (200 μM), in the continued presence of wortmannin hyperpolarized the cell from -46 to -77 mV. Tolbutamide (100 μM), applied after the BVT-induced hyperpolarization, recovered the membrane potential (to -40 mV). B, cell-attached recordings from CRI-G1 cells, following exposure of cells to 10 nM wortmannin for 15–20 minutes. Upper trace; in the continued presence of wortmannin, Nf.Po was 0.01 and 0.03 after 5 and 30 minutes respectively. Lower trace, application of BVT.12777 (100 μM) to cell-attached recording in the presence of 10 nM wortmannin resulted in KATP activation, with Nf.Po values of 0.01, 0.12 and 0.27 prior to, and 10 and 30 minutes after, BVT.12777, respectively. Addition of 100 nM wortmannin did not inhibit channel activity.