FIGURE 2.

Madagascine (0.3–100 μM) inhibited the constriction of rat mesenteric resistance arteries (MRAs) induced by 40 mM K⁺. The doses of madagascine were selected according to pre-experiments. Isolated rat MRAs with intact endothelium were perfused with Krebs solution and the perfusion pressure was stimulated by continuous perfusion of 40 mM K⁺. After the elevated perfusion pressure stabilized, Krebs solution containing 40 mM K⁺ and madagascine at a concentration of 0.3, 1, 3, 10, 30, or 100 μM was perfused, respectively. Acetylcholine (ACh, 1 nM) treatment is a bolus injection. Vasodilatation response to ACh confirms the intact of endothelium. Data are expressed as the mean ± SD and the response to Krebs solution was set as baseline. Other data are the relative values compared with baseline. ^∗∗p < 0.01 compared with 40 mM K⁺, n = 6 tissues.