Figure 4. Effects of AA metabolites on K_ATP channel activities in rat mesenteric arterial smooth muscle cells.

A, whole-cell total K⁺ currents in rat mesenteric arterial smooth muscle cells were elicited from −100 mV to + 40 mV at a holding potential of 0 mV at 10 mV increments under control conditions. Total K⁺ currents were enhanced by 1 μm AA and blocked by 10 μm glyburide (left column). Glyburide-sensitive K_ATP currents were obtained by digital subtraction of glyburide-insensitive components of K⁺ currents. AA (1 μm) increased vascular K_ATP currents (right column). B, whole cell total K⁺ currents were recorded from cells preincubated with 5 μm SKF525A for 60 min. AA failed to activate total K⁺ currents (left column). AA had no effect on vascular K_ATP currents (right column). C, vascular K_ATP channel I–V relationships showing the current densities before and after exposure to AA, with and without preincubation with SKF525A. n = 6 for all groups; ^*P < 0.05, AA versus baseline.