Fig. 6.

Comparison of vasomotor responses in mesenteric arterioles of wild-type and iPLA₂β knockout mice in vivo. Arteriolar diameters were measured using video microscopy. Superfusion with PE (100 μmol/l) constricted the vessels similarly in both wild-type (n = 10) and iPLA₂β^−/− (n = 10) mice. An intravenous bolus injection of ACh (16 μmol/l) dilated the wild-type vessels more than the knockout vessels, indicating that the in vivo vasodilatory response to ACh is attenuated in mice null for iPLA₂β. *P < 0.001 between groups by repeated-measures ANOVA.