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Kv3.4通道参与15--羟二十碳四烯酸诱导的大鼠肺动脉收缩

李倩, 毕海容, 张荣, 朱大岭

哈尔滨医科大学药学院. 哈尔滨；哈尔滨医科大学第二附属医院药学部. 哈尔滨；黑龙江省生物医药工程重点实验室. 黑龙江，哈尔滨 150086

摘要

通过组织浴槽血管环方法观察Kv3.4通道特异阻断剂BDS--Ⅰ对15--羟二十碳四烯酸(15--hydroxyeicosatetraenoic acid, 15--HETE)收缩肺动脉血管的影响；通过酶法分离、培养Wistar大鼠肺动脉血管平滑肌细胞(pulmonary artery smooth muscle cells, PASMCs)，RT--PCR和Western blot技术观察15--HETE对大鼠PASMCs上Kv3.4通道表达的影响，以探讨Kv3.4通道在15--HETE收缩肺动脉过程中的作用。结果如下：15--HETE以浓度依赖方式使肺动脉环张力增加，对缺氧组大鼠肺动脉环张力作用更为明显，与正常对照组相比差异显著；除去肺动脉内皮后，15--HETE引起血管收缩的强度较内皮完整时增强，呈剂量依赖性收缩反应；阻断Kv3.4通道可抑制15--HETE收缩肺动脉；15--HETE下调PASMCs膜上Kv3.4通道mRNA及蛋白质表达。上述观察结果提示Kv3.4通道参与由15--HETE引起的缺氧肺动脉血管收缩(hypoxic pulmonary vasoconstriction, HPV)。

关键词： 15-羟二十碳四烯酸; 电压门控性钾通道亚型; 肺动脉血管平滑肌细胞; 缺氧肺动脉血管收缩

Kv3.4 channel is involved in rat pulmonary vasoconstriction induced by 15--hydroxyeicosatetraenoic acid

Li Qian, Bi Hairong, Zhang Rong, Zhu Daling

College of Pharmacy. Harbin China；The Pharmarceutical Department of the Second Affiliated Hospital，Harbin Medical University. Harbin, China；Biopharmacy Engineering Key Laboratory of Heilongjiang Province. Harbin 150086, China

Abstract

We have reported that hypoxia increases the activation of 15-lipoxygenase (15-LO), which converts arachidonic acid (AA) into 15-hydroxyeicosatetraenoic acid (15-HETE) in small pulmonary arteries (PAs). Through inhibition of Kv channels, 15-HETE causes more robust concentration-dependent contraction of PA rings from the hypoxic compared to the normoxic controls. However, the subtypes of Kv channels inhibited by 15-HETE are incompletely understood. The aim of the present study was to identify the contribution of Kv3.4 channel in the process of pulmonary vasoconstriction induced by 15-HETE using the tension studies of PA rings from rat with Kv3.4 channel blocker in tissue bath; to explore the role of vascular endothelium in15-HETE-induced pulmonary vasoconstriction through denuded endothelia of PA rings; and to define the downregulation of 15-HETE on the expression of Kv3.4 channel in cultured pulmonary artery smooth muscle cells (PASMCs) with RT-PCR and Western blot. In the present study, healthy Wistar rats were divided randomly into two groups: Group A with normal oxygen supply and group B with hypoxia. Six days later, the rats were killed. Pulmonary artery rings were prepared for organ bath experiments. Firstly, different concentrations of 15-HETE (10~1 000 nmol/L) were added to the Krebs solution. The isometric tension was recorded using a four-channel force-displacement transducer. Then Kv3.4 channel blocker, 100 nmol/L BDS-Ⅰ, was added, followed by adding 1 mmol/L 15-HETE, and the isometric tension was recorded. Furthermore, RT-PCR and Western blot were employed to identify the influence of 15-HETE on the expression of Kv3.4 channel in cultured rat PASMCs.The results showed the PA tension was significantly increased both in groups A and B by 15-HETE in a concentration-dependent manner (P<0.05), especially in group B (P<0.05 compared to control); denuded endothelia enhanced 15-HETE concentration-related constrictions in rat PA rings; Kv3.4 channel blocker, BDS-Ⅰ, significantly decreased the PA ring constriction induced by 15-HETE (P<0.05); the expressions of Kv3.4 mRNA and protein in rat PASMCs were significantly downregulated by 15-HETE (P<0.05). Based on all the information above, we conclude that Kv3.4 channel is involved in vasoconstriction induced by 15-HETE in rat PAs.

Key words: 15-hydroeicosatetraenoic acid;Vvoltage-gated potassium channel subunits;Pulmonary artery smooth muscle cells;Hypoxic pulmonary vasoconstriction

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引用本文：

李倩, 毕海容, 张荣, 朱大岭. Kv3.4通道参与15--羟二十碳四烯酸诱导的大鼠肺动脉收缩[J]. 生理学报 2006; 58 (1): .

Li Qian, Bi Hairong, Zhang Rong, Zhu Daling. Kv3.4 channel is involved in rat pulmonary vasoconstriction induced by 15--hydroxyeicosatetraenoic acid. Acta Physiol Sin 2006; 58 (1): (in Chinese with English abstract).