title: Nitric oxide detection by DAF (diaminofluorescein) fluorescence in human myometrial tissue.
abstract: Nitric oxide (NO) is considered to be involved in the modulation of uterine contractility. In the present pilot study, the direct detection of intracellular NO in pregnant human myometrial tissues has been investigated by using the fluorescent indicator 4,5-diaminofluorescein-2 diacetate (DAF-2DA). Pregnant myometrial tissue samples were obtained during Cesarean sections between week 34 and 40 of gestation before the onset of labor. Living explants were loaded with 10 microM DAF-2DA, stimulated with 1 mM arginine, subsequently fixed with glutaraldehyde and examined by fluorescence microscopy. The presence of NO synthases (NOS) was studied by immunohistochemistry. After application of DAF-2DA, DAF fluorescence was located primarily in blood vessels and to a minor extent in myometrial cells. By immunohistochemistry, strong endothelial NOS (eNOS) staining was found in vessel walls. In myometrial cells weak staining of eNOS and inducible NOS was observed. We conclude that the direct NO detection by DAF-2DA provides a new and independent method to identify sites of NO production in myometrium and other heterogeneous tissues.
authors.affiliation: Department of Obstetrics & Gynecology, University Hospital Freiburg, Freiburg, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Schwendemann
authors.forename: Bernd
authors.initials: B
authors.lastname: Sehringer
authors.forename: Claudia
authors.initials: C
authors.lastname: Noethling
authors.forename: Hans Peter
authors.initials: HP
authors.lastname: Zahradnik
authors.forename: Wolfgang R
authors.initials: WR
authors.lastname: Schaefer
mesh_terms: D005260:Female; D019793:Fluorescein / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D007150:Immunohistochemistry; D007202:Indicators and Reagents / Q000737:chemistry; D008856:Microscopy, Fluorescence / Q000379:methods; D009215:Myometrium / Q000737:chemistry* / Q000201:enzymology / Q000378:metabolism; D009569:Nitric Oxide / Q000032:analysis* / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000032:analysis / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000032:analysis / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000032:analysis / Q000378:metabolism; D010865:Pilot Projects; D011247:Pregnancy
chemical_list: C414689:4,5-diaminofluorescein diacetate; D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D009569:Nitric Oxide; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D019793:Fluorescein