Antagonistic effects of tetrandrine on ouabain-induced contraction of coronary arterial strips
Abstract
Effects of tetrandrine (Tet) and verapamil (Ver) on ouabain (Oub)-induced contraction were studied in swine coronary arterial strips. Like Ver, Tet (10 VM-1.2 mM) relaxed the contraction induced by Oub 0.85 uM, antagonized the synergistic effect of Oub 85 nM and Ca2+ 2-16 mM. and depressed its response to electrical stimuli in the presence of Oub 85 nM. But its effects were less potent than those of verapamil. All these pharmacological actions of Tet and Verwere reversed by the addition of extra Ca2+ to the bath fluid medium. The results confirm that Tet is a new Ca2+ antagonist.
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