Fig. 5.

Inhibition of Ca²⁺_e-induced relaxation of PE-contracted mesenteric arteries by l-NIO. (A) Tracings of tension changes in a mesenteric artery segment from an eNOS^−/− mouse following contraction with 5 μM PE and cumulative additions of Ca²⁺_e. (B–D) Inhibition of Ca²⁺_e-induced relaxation by 10 μM l-NIO. [Ca²⁺]_e-response curves were generated from tracing data obtained in tissues from C57BL/6 (B), nNOS^−/− (C), and eNOS^−/− (D) mice mounted in PSS with 1 mM CaCl₂. l-NIO had a larger effect in tissues from C57BL/6 and nNOS^−/− mice than those from eNOS^−/− mice.