[Modifications of electromechanical coupling in the rabbit myocardium following cholesterol-oil diet during changing...

To characterize the electromechanical coupling in rabbit myocardium after a 12 weeks lasting lipid-rich diet the influence of increasing extracellular Ca2+ on isometric contractions of isolated trabeculae has been investigated. Only after lipid-rich diet the Ca2+-induced augmentation in isometric tension was accompanied by an increase in a Vmax equivalent, in the index of contractility dk/dtmax divided by K', and in the relaxation index -dk/dtmax divided by K. The results correspond with changes in the sarcoplasmic reticulum function reflected in a higher Ca2+ accumulating ability of isolated microsomes.