title: Contractile effects of endothelins on isolated human ureter.
abstract: The aim of our study was to investigate mechanism of action of endothelins 1, 2 and 3 on spontaneous activity, tone and intraluminal pressure of human ureter. Both longitudinal tension and intraluminal pressure were recorded from the isolated segments of proximal human ureter. Endothelins 1, 2 and 3 (5.35x10(-11) M - 5.05x10(-8) M) produced concentration-dependent tonic contraction and sustained increase in intraluminal pressure of isolated preparations of human ureter. Endothelins 1 and 3 produced also concentration-dependent inhibition of spontaneous, phasic contractions of the isolated preparations. Selective antagonist of ET(A) receptors BQ123 and selective antagonist of ET(B) receptors BQ788 produced significant inhibition of endothelin-1-induced tonic contraction (pA(2)=8.80 and 6.55, respectively) and increase in intraluminal pressure (pA(2)=8.68 and 7.02, respectively), while they did not affect endothelin-1-induced inhibition of spontaneous activity. Endothelin 1 produces increase in tone and intraluminal pressure of isolated human ureter acting on both ET(A) and ET(B) receptors, the first one being functionally more important. Only endothelins 1 and 3 inhibit spontaneous, phasic activity of human ureter, but this effect was not blocked by selective antagonists of ET(A) and ET(B) receptors.
authors: Pharmacology Department, Medical Faculty, University of Kragujevac, Kragujevac, Serbia. slobnera@eunet.rs
authors: S M
authors: SM
authors: Jankovic
authors: S V
authors: SV
authors: Jankovic
authors: V
authors: V
authors: Stojanovic
authors: D
authors: D
authors: Stojadinovic
authors: M
authors: M
authors: Stojadinovic
authors: D
authors: D
authors: Canovic
authors: S
authors: S
authors: Stefanovic
mesh_terms: D000368:Aged; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000494:pharmacology / Q000502:physiology; D019333:Endothelin-2 / Q000494:pharmacology / Q000502:physiology; D019334:Endothelin-3 / Q000494:pharmacology / Q000502:physiology; D016232:Endothelins / Q000494:pharmacology* / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D017466:Receptors, Endothelin / Q000502:physiology; D014513:Ureter / Q000187:drug effects* / Q000502:physiology
chemical_list: D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D019333:Endothelin-2; D019334:Endothelin-3; D016232:Endothelins; D017466:Receptors, Endothelin