Figure 2
Tension versus strain measurements to determine stiffness. After culture for 3 days, tension measurements were collected from intact mucosa during sequential cycles (a,b) of stepwise lengthening followed by stepwise shortening of the same esophageal mucosa strip. Lengthening was reversed at a force threshold set to avoid tissue damage. Shortening was reversed as the force approached zero. The step tracings indicate the length (L, right y-axis) at which the tissue was held for 2 minute intervals as length was changed in 0.72 mm increments. (a) In strain cycle 1, tissue tension (black line) but not length (red line) reached baseline on stepping down and (b) this remained the case in strain cycle 2. (c) 1 μM carbachol increases tension and shortening to less than the starting length. (d) In strain cycle 3 the tissue shortens to the starting length. (e) Integrated tension measurements plotted as a function of strain. (f) Plots generated from panel e data by subtracting cycle 2 from cycle 1 (basal) or cycle 3 (induced). (g) LSM bundle tension versus strain plots collected after culture for 10 days. (h) Contribution of smooth muscle to tissue tension in in basal and induced states for the LSM in panel g.
