A, representative cross-sections of Masson trichrome stained MCAs. B and C, summary of W/L ratios (B) and wall thickness (C) in diabetic and control MCAs with and without ET receptor antagonism. Results are given as mean ± S.E.M., n = 6–8 in all groups except control + A192621 = 3. *, p < 0.05 versus control; **, p < 0.0001 disease and treatment interaction. ξ, p < 0.05 versus vehicle; ψ, p < 0.05 versus diabetes + A192621.