title: The effects of bumetanide on human umbilical artery contractions.
abstract: The authors investigate the effect of bumetan ide, an inhibitor of NKCC1 and a loop diuretic, on the tone of human umbilical artery (HUA). Rings of HUA (n = 35) from vaginal deliveries were suspended for isometric tension recordings in organ baths. Cumulative concentration-response curves to serotonin, histamine, and KCl were performed in the absence (control) or in the presence of bumetanide. The relaxant effect of bumetanide was also evaluated in serotonin- and histamine-induced contractions. Bumetanide inhibited HUA tone in serotonin- and histamine-induced contractions with significant changes in the potency (pD(2)) and maximum contractile response (E(max)) values. However, only pD( 2) values for KCl-induced contraction significantly changed in the presence of bumetanide. Bumetanide caused concentration-dependent and sustained relaxations in serotonin-induced contraction; however, there was refractoriness in histamine-induced contraction. These findings raise the possibility that NKCC1 may play a role in the regulation of the umbilical artery tone.
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy, Gazi University, Ankara, Turkey.
authors.forename: Emel
authors.initials: E
authors.lastname: Dayioglu
authors.forename: C Kemal
authors.initials: CK
authors.lastname: Buharalioglu
authors.forename: Ferit
authors.initials: F
authors.lastname: Saracoglu
authors.forename: Fatma
authors.initials: F
authors.lastname: Akar
mesh_terms: D000293:Adolescent; D000328:Adult; D002034:Bumetanide / Q000494:pharmacology*; D005260:Female; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D011189:Potassium Chloride / Q000494:pharmacology; D011247:Pregnancy; D012701:Serotonin / Q000494:pharmacology; D049994:Sodium Potassium Chloride Symporter Inhibitors / Q000494:pharmacology*; D014469:Umbilical Arteries / Q000187:drug effects* / Q000502:physiology
chemical_list: D049994:Sodium Potassium Chloride Symporter Inhibitors; D002034:Bumetanide; D012701:Serotonin; D011189:Potassium Chloride; D006632:Histamine