1. [Calcium-activated chloride channels are involved in two-phase hypoxic pulmonary vasoconstriction in rat pulmonary arteries].
- Author
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Ying L, Yao HX, Huang LJ, Ma YC, He JB, Chen D, Chen HE, Wang Y, and Wang WT
- Subjects
- Animals, Glycolates pharmacology, Male, Norepinephrine pharmacology, Rats, Rats, Sprague-Dawley, Vasodilation, Chloride Channels physiology, Hypoxia physiopathology, Pulmonary Artery physiopathology, Vasoconstriction
- Abstract
The aim of the present study was to investigate the roles of calcium-activated chloride channels (Cl(Ca)) in the two-phase hypoxic pulmonary vasoconstriction (HPV). The second pulmonary artery branches were dissected from male Sprague-Dawley rats, and the changes in vascular tone were measured by using routine blood vascular perfusion in vitro. The result showed that, under normoxic conditions, Cl(Ca) inhibitors (NFA and IAA-94) significantly relaxed second pulmonary artery contracted by norepinephrine (P < 0.01), but merely had effects on KCl-induced second pulmonary artery contractions. A biphasic contraction response was induced in second pulmonary artery ring pre-contracted with norepinephrine exposed to hypoxic conditions for at least one hour, but no biphasic contraction was observed in pulmonary rings pre-contracted with KCl. NFA and IAA-94 significantly attenuated phase II sustained hypoxic contraction (P < 0.01), and also attenuated phase I vasodilation, but had little effect on phase I contraction. These results suggest that Cl(Ca) is an important component forming phase II contraction in secondary pulmonary artery, but not involved in phase I contraction.
- Published
- 2014