Effects of trichothecene mycotoxins on the ex vivo vascular smooth muscle responses to beta-adrenergic agonists.

The ex vivo biophysical response of isolated rat aorta to T-2 toxin, diacetoxyscirpenol (DAS) and Roridin-A were determined. Roridin-A caused a dose-dependent relaxation of precontracted (30 mM KCl) aorta, while T-2 toxin and DAS were without effect. On the other hand, the relaxation response of aorta to isoproterenol and sodium fluoride is impaired in the presence of T-2 toxin or DAS. Roridin-A did not alter the relaxation response to isoproterenol or sodium fluoride. These experiments suggest that macrocyclic trichothecenes (e.g., Roridin-A) are capable of altering vascular smooth muscle tone directly, while simple trichothecenes (e.g., T-2 toxin, DAS) interfere with beta-adrenergic responses.