Figure 4.

Dilation of cerebral (pial) arterioles (in vivo) from M5R^−/− mice and their wild-type littermates. (A) Acetylcholine-induced dilation responses of cerebral arterioles were abolished in M5R^−/− mice. (B) In contrast, ADP-dependent vasodilator effects were largely retained in M5R^−/− mice. Values are expressed as means ± SEM (n = 8 per dose and genotype). *, P < 0.05 (vs. wild-type; ANOVA followed by posthoc Bonferroni's t test).