title: Evidence for nitric oxide mediation of contractile activity in isolated strips of the human Fallopian tube.
abstract: Endogenously produced nitric oxide (NO) induces relaxation in smooth muscle in various organs. The purpose of this study was to investigate whether a NO-mediated relaxation system exists in the human Fallopian tube. To study contractility, the isthmic portion of the tube was obtained from 23 fertile women during operations due to benign non-tubal diseases. Tubal smooth muscle strips were mounted in tissue chambers containing HEPES buffer and connected to a Grass transducer for the isometric registration of contractile activity. By adding L-arginine (the substrate for NO synthesis) or N-nitro-L-arginine methyl ester (L-NAME; an inhibitor of NO synthesis) to the tissue chambers, changes in tubal contractility were monitored. The addition of L-NAME caused increased tubal contractility, while L-arginine, after an initial transient increase in tonus, caused relaxation of the strips. Using immunohistochemistry, NO synthase, the enzyme that catalyses the production of NO from L-arginine, was identified in tubal tissue cells. These results indicate that a NO-dependent relaxation system exists in the Fallopian tube and that NO may play a role as a mediator of tubal contractility.
authors.affiliation: Department of Obstetrics and Gynecology, University of Göteborg, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Ekerhovd
authors.forename: M
authors.initials: M
authors.lastname: Brännström
authors.forename: M
authors.initials: M
authors.lastname: Alexandersson
authors.forename: A
authors.initials: A
authors.lastname: Norström
mesh_terms: D004791:Enzyme Inhibitors / Q000494:pharmacology; D005187:Fallopian Tubes / Q000502:physiology*; D005260:Female; D006801:Humans; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D019331:NG-Nitroarginine Methyl Ester