Alterations in myocardial ultrastructure and protein expression after a single injection of isoproterenol.

Immunochemical and electron microscopic characterization of rat myocardium was conducted 2 h and 3 weeks after a single injection of isoproterenol in rats. The relative content of several myospecific proteins (KRP--kinase-related protein, desmin), cytoskeletal proteins (tubulin, vinculin, myosin light chain kinase--MLCK) and extracellular matrix protein fibronectin was determined by immunoblotting. Two hours after injection of 50 mg/kg isoproterenol a destruction of some cardiomyocytes, contracture of myofibrils and mild edema of intercellular space was observed.

Alterations in myocardial cytoskeletal and regulatory protein expression following a single Doxorubicin injection.

Immunochemical and ultrastructural studies of the rat heart after a single injection of doxorubicin (2.2 or 0.44 mg/kg) were performed.

Smooth muscle myosin filament assembly under control of a kinase-related protein (KRP) and caldesmon.

Kinase-related protein (KRP) and caldesmon are abundant myosin-binding proteins of smooth muscle. KRP induces the assembly of unphosphorylated smooth muscle myosin filaments in the presence of ATP by promoting the unfolded state of myosin. Based upon electron microscopy data, it was suggested that caldesmon also possessed a KRP-like activity (Katayama et al.