title: Inhibition of crossbridge function in the normal human heart by hypoxic endothelial superfusate.
abstract: Endothelial cells release diffusible substances which modulate myocardial function. Oxygen pressure is one important factor for stimulation and modulation of endothelial function. Here we investigated the effects of a superfusate obtained from hypoxic (pO(2) 40-50 mmHg) porcine endothelial cell culture on human myocardial crossbridge cycling rate. Isometric force development and the rate constant for tension development of demembranated multicellular fibers from the left myocardium of a normal human heart were determined from the low-tension rigor by photolytic release of ATP from caged-ATP. Incubation with hypoxic or normoxic superfusates did not change maximal isometric force development. However, rate constant of tension development of the normal human heart fibers significantly decreased to 43.3% upon incubation with the hypoxic but not normoxic endothelial cell superfusate.
authors.affiliation: Charité, Campus Berlin-Buch, Franz-Volhard-Clinic, Humboldt-University of Berlin, Berlin, 13122, Germany.
authors.forename: U B
authors.initials: UB
authors.lastname: Zacharzowsky
authors.forename: A M
authors.initials: AM
authors.lastname: Shah
authors.forename: H
authors.initials: H
authors.lastname: Haase
authors.forename: I
authors.initials: I
authors.lastname: Morano
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D015687:Cell Hypoxia / Q000502:physiology*; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006321:Heart / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism; D009200:Myocardial Contraction; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D009218:Myosins / Q000378:metabolism*; D010782:Photolysis; D013552:Swine
chemical_list: D017077:Culture Media, Conditioned; C029273:P(3)-1-(2-nitro)phenylethyladenosine 5'-triphosphate; D000255:Adenosine Triphosphate; D009218:Myosins; D002118:Calcium