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Effect of 15--HETE on potassium channels of rabbit pulmonary arterial smooth muscles during hypoxia

Han Weina, Li Xianghui, Jiang Zhuying, Ji Hongyu, Huang Lijun, Wang Zhimin, Zhu Daling

College of Pharmacy,Harbin Medical University.Harbin 150086,Heilongjiang；China

Abstract

This study investigated the role of 15-hydroxyeicosatetraenoic acid (15-HETE) in rabbit pulmonary arterial smooth muscle cells (PASMCs) under hypoxia by using organ bath and whole cell patch-clamp techniques. Neonatal rabbits born into normoxic environment were transferred after first feeding into normal and hypoxic environments with respectively 0,21 and 0.12 fractional inspired oxygen (FiO_(2)). Pulmonary arteries were extracted after 9 d and cut into rings 1.0～1.5 mm in length for organ bath experiments.Whole cell patch-clamp technique was used to measure the potassium current in the freshly dispersed rabbit PASMCs. The results showed that 15-HETE-induced vasoconstriction was blocked by 4-aminopyridine (5 mmol/L), a K_(V) channel blocker. The K_(ATP) channel blocker glyburide (1 #mu#mol/L) and the BK_(Ca) channel blocker tetraethylammonium (10 mmol/L) did not abolish this vasoconstriction. 15-HETE decreased the whole-cell voltage-gated K~(+) current in the PASMCs. These findings demonstrate that hypoxia blocks K_(V) channels through a 15-HETE mediated mechanism, leading to PA vasoconstriction.

Key words: 15-HETE;Hypoxia;pulmonary arterial rings;patch-clamp technique;ionic channel blocker

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Citing This Article：

Han Weina, Li Xianghui, Jiang Zhuying, Ji Hongyu, Huang Lijun, Wang Zhimin, Zhu Daling. Effect of 15--HETE on potassium channels of rabbit pulmonary arterial smooth muscles during hypoxia. Acta Physiol Sin 2004; 56 (6): (in Chinese with English abstract).