Vasoconstriction of carotid artery induced by hydroperoxides

The influence of hydroperoxides (hydrogen peroxide, t-butylhydroperoxide) on tone of arterial smooth muscle was studied. The results of the experiments which were performed with segments of rabbit carotid arteries under isometric conditions show that peroxide concentrations higher than 10(-4) M induced vasoconstriction. These contractions were reversible when glucose was present in the superfused solution. In the absence of glucose a long-lasting increase in tone was found. The contraction response persisted even in Ca2+-free solution. These results indicate a stimulatory effect of hydroperoxides on vascular smooth muscle probably related to a liberation of intracellularly bound calcium ions.