Fig. 5.
Penitrem A has no effect on KV1.5 or KATP channels. A, whole-cell recordings were made from HEK 293 cells transfected with hKV1.5. Representative KV1.5 currents in the absence or presence of 1 μM penitrem A are shown. B, group data (n = 5 cells) show that penitrem A (1 μM) has no effect on KV1.5 current. C, whole-cell recordings were made from mouse aortic smooth muscle cells. Cells were dialyzed with an ATP-free pipette solution to activate KATP current in symmetrical 140 mM K+. Current was recorded in response to voltage ramps from −100 to +100 mV under control conditions, with the addition of 1 μM penitrem A and 10 μM glibenclamide. Linear inward KATP current between −100 and −40 mV is shown. D, group data (n = 7 cells) show that glibenclamide, but not penitrem A, inhibits KATP channels in smooth muscle. *, p < 0.05 versus control by one-way ANOVA.