Fig. 7.

Agonist-induced increases in stress and stiffness with Src kinase inhibitor pretreatment are higher with aging. Thoracic aortas pretreated with 10 μM PP2 contract and stiffen less in young but not old mice in the presence of maximal activation (PE + l-NAME). As a result, maximal active stress (A) and stiffness (B) increase >2-fold with aging under these conditions with HFLA measurements. Also shown for comparison are control maximal active data in the absence of PP2 (PP2−), reproduced from Fig. 5, A and B. Absolute values are means ± SE; n = 3 young, 4 old. ***P < 0.001 with aging; ‡P < 0.05, ‡‡‡P < 0.001 with addition of PP2.