Figure 4. Stretch-induced titin phosporylation.
In a Langendorff preparation an acute volume load causes a brisk rise in LV end-diastolic pressure (LVEDP), which gradually falls over a 15 minute period. Subsequent removal of the volume load causes LVEDP to drop below baseline without full recovery over the next 10 minutes period (Left hand panel; *,†,‡: p<0.001). In stretched muscle strips, titin phosphorylation (total and isoform specific) was signficantly higher than in non-stretched muscle strips (Middle panel) as also evident from Pro-Q diamond staining (Right hand panel). Stretch induced effects disappeared following inhibition of PKG (PKGi) and were absent in hypertrophied myocardium.