title: [Role of calcium-activated chloride channels in the regulation of pulmonary vascular tone in rats].
abstract: OBJECTIVE
  To investigate the role of calcium-activated chloride channels and the Cl- channel blockers niflumic acid (NFA) and indanyloxyacetic acid (IAA-94) in the regulation of vascular contraction induced by phenylephrine (PE).
  
  
  METHODS
  The PE-induced contraction in rat pulmonary artery was observed by using routine blood vascular perfusion in vitro. The fluorescence Ca2+ indicator Fura-2/AM was used to observe intracellular free Ca2+ concentration ([Ca2+]i) of rat pulmonary artery smooth muscle cells (PASMCs) which were obtained by the acute enzyme separation method (collagenase I plus papain) on NFA and IAA-94 effects on PE-induced contraction. Changes of [Ca2+]i in PASMCs were measured by spectrofluorometry.
  
  
  RESULTS
  The anion channel blockers NFA and IAA-94 produced inhibitory effects on PE-induced contractions in the pulmonary artery. NFA and IAA-94 negligibly affected the KCl-induced pulmonary artery contractions. PE could increase [Ca2+]i but NFA and IAA-94 negligibly affected it.
  
  
  CONCLUSIONS
  Calcium-activated chloride channels contribute to the agonist-induced pulmonary artery contractions under physiological conditions, which may be a new clue to investigate the hypoxic pulmonary vasoconstriction.
authors.affiliation: Respiratory Disease Research Institute, Affiliated Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Yang
authors.forename: Zhen-Xiang
authors.initials: ZX
authors.lastname: Zhang
authors.forename: Yong-Jian
authors.initials: YJ
authors.lastname: Xu
authors.forename: Tao
authors.initials: T
authors.lastname: Ye
authors.forename: Ya-Qing
authors.initials: YQ
authors.lastname: Li
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology; D018118:Chloride Channels / Q000502:physiology*; D006016:Glycolates / Q000494:pharmacology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D009544:Niflumic Acid / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011651:Pulmonary Artery / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction
chemical_list: D018118:Chloride Channels; D006016:Glycolates; D010656:Phenylephrine; D009544:Niflumic Acid; C015765:MK 473; D002118:Calcium