Prevention of PDBu-induced vasoconstriction. Vessels with basal tone were pre-treated for 20 minutes with (A) Gö-6983 (3 μM, n = 6), (B) nifedipine (1 μM, n = 5), or (C) H-1152 (3 μM, n = 7), followed by treatment with PDBu (0.1 μM) for 20 minutes. *P < 0.05 versus control. #P < 0.05 versus nifedipine pre-treatment.