title: The presence of platelet-activating factor binding sites in human myometrium and their role in uterine contraction.
abstract: It has recently been suggested that platelet-activating factor is involved in a number of processes associated with reproductive biology. We have demonstrated a critical role for this autacoid in the initiation and maintenance of parturition both in animals and man. In the present investigation, it has been demonstrated that platelet-activating factor affects contraction in strips of human myometrium at concentrations as low as 10(-10) mol/L. A platelet-activating factor receptor has been identified and characterized in human myometrium. Platelet-activating factor acts to cause an increase in intracellular Ca2+ concentration of isolated myometrial smooth muscle cells in culture and an increase in the phosphorylation of the 20 kd light chain of myosin in a concentration-dependent fashion. The presence of platelet-activating factor receptors in human myometrium, the observed increase in Ca2+ concentration and phosphorylation of myosin light chain in the presence of platelet-activating factor provide further support for the importance of this autacoid in the initiation of parturition.
authors.affiliation: Department of Biochemistry, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas 75235-9051.
authors.forename: Y P
authors.initials: YP
authors.lastname: Zhu
authors.forename: R A
authors.initials: RA
authors.lastname: Word
authors.forename: J M
authors.initials: JM
authors.lastname: Johnston
mesh_terms: D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D009215:Myometrium / Q000166:cytology / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D009994:Osmolar Concentration; D010766:Phosphorylation; D010972:Platelet Activating Factor / Q000378:metabolism* / Q000494:pharmacology; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled; D014590:Uterine Contraction / Q000187:drug effects
chemical_list: D010972:Platelet Activating Factor; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; C039351:platelet activating factor receptor; D009218:Myosins; D002118:Calcium