title: [Permeability characteristics of the endocardium and the myocardial capillaries to horseradish peroxidase in fetal and postnatal rats].
abstract: After intravenous or intracardial application of horseradish peroxidase (HRP) at the myocardial capillaries of fetal, juvenile and adult rats a fast transport of the tracer into the interstite can be observed. In the fetal cases the transport takes place especially through the interendothelial junctions, in the postnatal cases a considerably amount of the peroxidase traversed also by plasmalemmal vesicles. In adults the T-tubules of the myocytes are labelled already after 15 min of circulation. From fetal stages up to adults the junctions of the endocardium are well permeable to HRP. After a short circulation time we found large deposits of reaction product in the subendocardial space. The reasons for the different permeability of fetal heart and skeletal muscle capillaries were discussed.
mesh_terms: D000375:Aging; D000818:Animals; D002196:Capillaries / Q000378:metabolism / Q000648:ultrastructure; D002199:Capillary Permeability; D003331:Coronary Vessels / Q000378:metabolism* / Q000648:ultrastructure; D004699:Endocardium / Q000196:embryology / Q000378:metabolism* / Q000648:ultrastructure; D004727:Endothelium / Q000648:ultrastructure; D006321:Heart / Q000196:embryology; D006735:Horseradish Peroxidase / Q000378:metabolism*; D007365:Intercellular Junctions / Q000648:ultrastructure; D008854:Microscopy, Electron; D010544:Peroxidases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D006735:Horseradish Peroxidase; D010544:Peroxidases
vernacular_title: Permeabilitätseigenschaften des Endokards und von Capillaren des Myokards bei fetalen und postnatalen Ratten für Meerrettichperoxidase.