External ATP antagonizes the effect of potassium channel openers in guinea-pig ventricular papillary muscle. |
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| Authors: | A Bott M Eltze P Illes |
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| Affiliation: | Department of Pharmacology, Byk Gulden Pharmaceuticals, Konstanz, Germany. |
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| Abstract: | Right ventricular papillary muscles of the guinea-pig heart were electrically stimulated. Cromakalim 10-100 microM and Ro 31-6930 3 microM depressed the contractile force and shortened the duration of action potentials. Glibenclamide 0.3-3 microM, ATP 100 microM and alpha, beta-methylene ATP (alpha, beta-meATP) 30 microM antagonized these effects. Suramin 300 microM failed to reverse the alpha, beta-meATP-evoked antagonism of the action of cromakalim. It is concluded that both intra- and extracellular ATP may interfere with potassium channel openers and that extracellular ATP does not act via the known P2-purinoceptor subtypes. |
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