Pharmacology Department, Medical Faculty, University of Kragujevac, Kragujevac, Serbia.
Physiol Res. 2011;60(6):933-9. doi: 10.33549/physiolres.932144. Epub 2011 Oct 12.
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.
我们研究的目的是研究内皮素 1、2 和 3 对人输尿管自发性活动、张力和腔内压力的作用机制。从人输尿管的近端分离段记录纵向张力和腔内压力。内皮素 1、2 和 3（5.35x10(-11) M - 5.05x10(-8) M）产生浓度依赖性紧张性收缩，并持续增加人输尿管分离标本的腔内压力。内皮素 1 和 3 还产生浓度依赖性抑制分离标本的自发性、阵发性收缩。内皮素 A 受体的选择性拮抗剂 BQ123 和内皮素 B 受体的选择性拮抗剂 BQ788 显著抑制内皮素 1 引起的紧张性收缩（pA(2)=8.80 和 6.55）和腔内压力增加（pA(2)=8.68 和 7.02），而它们不影响内皮素 1 引起的自发性活动抑制。内皮素 1 通过作用于 ET(A)和 ET(B)受体，增加人输尿管的张力和腔内压力，前者在功能上更为重要。只有内皮素 1 和 3 抑制人输尿管的自发性、阵发性活动，但这种作用不能被内皮素 A 和内皮素 B 受体的选择性拮抗剂阻断。
