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Selective inhibition by ethylisopropylamiloride of the positive inotropic effect evoked by low concentrations of ouabain in rat isolated ventricles
Author(s) -
Finet Michel,
Godfraind Théophile
Publication year - 1986
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 - 10.1111/j.1476-5381.1986.tb11153.x
Subject(s) - ouabain , inotrope , isoprenaline , chemistry , medicine , endocrinology , pharmacology , sodium , biology , stimulation , organic chemistry
1 The biphasic positive inotropic effect of ouabain has been studied in rat ventricular strips in the presence of ethylisopropylamiloride (EIPA) an inhibitor of Na + /H + exchange. 2 EIPA (10–20 μM) depressed dose‐dependently the high affinity component of the ouabain inotropic effect, whereas it did not significantly modify the low affinity inotropic effect related to high concentrations of ouabain. 3 At the EIPA concentrations studied, there was no observable modification of the inotropic effect of Bay K 8644 (10 nM, 0.3 μM) or of isoprenaline (10 nM, 1 μM). 4 These results indicate that the inotropic effect of ouabain resulting from its interaction with high affinity sites is selectively sensitive to EIPA.