Figure 9. Effect of 1 μm ryanodine, 1 μm nicardipine, and a combination of the two blockers on 30 μm PE-induced contraction in mesenteric (A; n= 3–6), caudal (B; n= 4–6) and aortic arteries (C; n= 4).

After ryanodine treatment (see Methods), 20 mm caffeine no longer evoked a contraction. After nicardipine treatment (see Methods), high K⁺-induced contraction was no longer elicited. +rya and +nic represents, respectively, the contraction of ryanodine- and nicardipine-treated arteries with ± 1 SEM (see Methods). +rya+nic represents a contraction of arteries treated with first ryanodine and then nicardipine in the presence of ryanodine. In aorta (C), +Y and +rya+Y represent, respectively, a contraction of aorta treated with 10 μm Y27632 and a combination of ryanodine and Y27632.