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[Effect of chronic intermittent hypobaric hypoxia on contractile activity of arteries in rats.] [Article in Chinese]

SONG Shi-Jun, XU Ying, LI Fang-Fang, YUAN Fang, ZHOU Zhao-Nian, ZHANG Yi^*

Department of Physiology； Department of Biochemistry and Molecular Biology, Basic Medical College, Hebei Medical University, Shijiazhuang 050017, China； Laboratory of Hypoxia Physiology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China

Abstract

The present study is aimed to investigate the effect of chronic intermittent hypobaric hypoxia (CIHH) on contractile activities in isolated thoracic aorta and pulmonary artery rings and the underlying mechanism in rats. Sprague-Dawley (SD) rats were randomly divided into 4 groups: control group (CON), 14 days CIHH treatment group (CIHH14), 28 days CIHH treatment group (CIHH28) and 42 days CIHH treatment group (CIHH42). CIHH rats were exposed to hypoxia in a hypobaric chamber simulating 5 000 m altitude, 6 h daily for 14, 28 and 42 d, respectively. After artery rings were prepared from pulmonary artery and thoracic aorta, the contractile activity of the artery rings was recorded using organ bath technique. Results are shown as follows. (1) There were no significant differences of noradrenaline (NA)- and KCl-induced contractions in thoracic aorta and pulmonary artery rings among CIHH and CON rats. (2) Angiotensin Ⅱ (ANGⅡ)-induced contraction in thoracic aorta rings, not in pulmonary artery rings, of CIHH rats was decreased compared with that in CON rats. There was no significant difference of ANGⅡ-induced contraction in thoracic aorta rings among CIHH rats. (3) Inhibitory effect of CIHH on ANGⅡ-induced contraction in thoracic aorta rings was endothelium-independent, and was reversed by glibenclamide (Gli), an ATP-sensitive potassium channels (KATP) blocker, and L-NAME, a NO synthase inhibitor, but not by indomethacin (Indo), a cyclooxygenase inhibitor. These results suggest that CIHH attenuates the contraction induced by ANGⅡ in thoracic aorta rings of rat, which is related to the opening of KATP channel and the increased production of NO.

Key words: intermittent hypoxia; aorta; ATP-sensitive potassium channel; angiotensin Ⅱ; nitric oxide; rats

Received: 2011-02-24　　Accepted: 2011-04-21

Corresponding author: 张翼　　E-mail: zhyhenry@hotmail.com

Citing This Article：

SONG Shi-Jun, XU Ying, LI Fang-Fang, YUAN Fang, ZHOU Zhao-Nian, ZHANG Yi. [Effect of chronic intermittent hypobaric hypoxia on contractile activity of arteries in rats.] [Article in Chinese]. Acta Physiol Sin 2011; 63 (3): 205-210 (in Chinese with English abstract).