Fig. 5.

Endothelial-dependent dilation (acetylcholine 1 × 10⁻⁹ to 1 × 10⁻⁴ M) in untreated and BQ-123-treated carotid arteries from old mice (A) (dose-response curve of young mice is provided as a reference), and untreated and BQ-123-treated carotid arteries from young mice (B). C: endothelial-independent dilation (sodium nitroprusside, 1 × 10⁻¹⁰ to 1 × 10⁻⁴ M) of carotid arteries isolated from young and old mice. D: maximal dilation to acetylcholine in untreated and BQ-123-treated carotid arteries from young and old mice. E: sensitivity (IC₅₀) to acetylcholine-mediated dilation in untreated and BQ-123-treated carotid arteries from young and old mice. Values are means ± SE. *P < 0.05 vs. young untreated mice. ‡P < 0.05 vs. untreated old mice. †P < 0.05 vs. young untreated mice.