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Role of eicosanoids in alteration of membrane electrical properties in isolated mesenteric arteries of salt‐loaded, Dahl salt‐sensitive rats
Author(s) -
Fujii Koji,
Onaka Uran,
Ohya Yusuke,
Ohmori Susumu,
Tominaga Mitsuhiro,
Abe Isao,
Takata Yutaka,
Fujishima Masatoshi
Publication year - 1997
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0701023
Subject(s) - medicine , mesenteric arteries , chemistry , endocrinology , phentolamine , thromboxane a2 , depolarization , tetrodotoxin , prostaglandin , contraction (grammar) , membrane potential , thromboxane , antagonist , biophysics , receptor , biochemistry , biology , platelet , artery
The role of eicosanoids in altered membrane electrical properties of Dahl salt‐sensitive (DS) rats was investigated, by use of conventional microelectrodes technique, in isolated superior mesenteric arteries of DS rats and Dahl salt‐resistant (DR) rats fed either a high or low salt diet. The membrane was significantly depolarized in salt‐loaded DS rats compared with the other three groups. In addition, the arteries of salt‐loaded DS rats exhibited spontaneous electrical activity. Spontaneous electrical activity in salt‐loaded DS rats was inhibited by the following: indomethacin, a cyclo‐oxygenase inhibitor; ONO‐3708, a prostaglandin H 2 /thromboxane A 2 receptor antagonist; OKY‐046, a thromboxane A 2 synthase inhibitor; nicardipine, a Ca 2+ ‐channel antagonist and by Ca 2+ ‐free solution. In addition, spontaneous electrical activity was enhanced by a thromboxane A 2 analogue and by prostaglandin H 2 . Spontaneous electrical activity was unaffected by phentolamine, atropine and tetrodotoxin. Membrane potential in arteries of salt‐loaded DS rats was not affected by either indomethacin or ONO‐3708. Spontaneous contraction, sensitive to indomethacin, was present, and contractile sensitivity to high potassium solution was enhanced in arteries of salt‐loaded DS rats. These findings suggest that eicosanoid action, together with membrane depolarization, may lead to the activation of voltage‐dependent Ca 2+ ‐channels, thereby causing spontaneous electrical activity in mesenteric arteries of salt‐loaded DS rats. In addition, tension data suggest that these changes in membrane properties are related to enhanced contractile activities in salt‐loaded DS rats. Mechanisms of depolarization remain to be determined.British Journal of Pharmacology (1997) 120 , 1207–1214; doi: 10.1038/sj.bjp.0701023