Differential effects of trichothecenes on the canine cardiac action potential.
We investigated the hypothesis that trichothecenes directly alter cardiac electrical activity. Action potentials were recorded from electrically stimulated canine false tendons before, during and after exposure to trichothecenes (1.0 mg/l). Action potentials recorded prior to and 60 min after exposure to trichothecenes were compared statistically. T-2 toxin decreased resting potentials in interventricular septum cells (7%), decreased action potential durations in papillary muscle cells (19%) and decreased both in false tendon cells (11% and 27%, respectively). Scirpentriol shortened durations of action potentials recorded in false tendon cells (24%), but had no other effects on any of the cell types tested. T-2 tetraol shortened the duration of interventricular septum cell action potentials (35%), but had no significant effects on other cardiac cells. Adenosine-5'-triphosphate (ATP) (final concentration 1100 mg/l) reversed all the effects of the trichothecenes on canine cardiac action potentials. These action potential changes may reflect a deficit of high energy phosphate and directly contribute to trichothecene-induced arrhythmias.