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The mechanism of action of cantharidin in smooth muscle
Author(s) -
Knapp Jörg,
Bokník Peter,
Huke Sabine,
Lüss Hartmut,
Müller Frank U.,
Müller Thorsten,
Nacke Peter,
Schmitz Wilhelm,
Vahlensieck Ute,
Neumann Joachim
Publication year - 1998
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.0701668
Subject(s) - cantharidin , myosin , myosin light chain kinase , phosphorylation , biology , cardiac muscle , myocyte , microbiology and biotechnology , biochemistry , medicine , chemistry , endocrinology , ecology
1 The aim of this study was to investigate the mechanism(s) of the vasoconstrictor effect of cantharidin in bovine preparations. 2 Catalytic subunits of protein phosphatase type 1 (PP 1) and type 2A (PP 2A) were immunologically identified in coronary arteries, isolated smooth muscle cells and ventricular myocardium. 3 The mRNAs coding for catalytic subunits of PP 1α, PP 1β and PP 2Aα were identified by hybridization with specific cDNA‐probes in total RNA from coronary arteries, isolated smooth muscle cells and ventricles. 4 The activities of catalytic subunits of PP 1 and PP 2A separated by column chromatography from coronary arteries, isolated smooth muscle cells and ventricles were inhibited by cantharidin in a concentration‐dependent manner. 5 Cantharidin increased the phosphorylation state of smooth muscle proteins including the regulatory light chains of myosin in 32 P‐labelled intact smooth muscle cells in a concentration‐dependent manner. 6 Cantharidin did not affect cytosolic calcium concentrations in aortic smooth muscle cells. 7 It is suggested that cantharidin contracts smooth muscle preparations by increasing the phosphorylation state of regulatory proteins due to inhibition of phosphatase activities. Thus, cantharidin might be a useful tool to study the function of phosphatases in smooth muscle.British Journal of Pharmacology (1998) 123 , 911–919; doi: 10.1038/sj.bjp.0701668