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).