EFFECTS OF VITAMIN-E-DEFICIENCY ON VASOMOTOR ACTIVITY AND ULTRASTRUCTURAL ORGANIZATION OF RAT THORACIC AORTA

1 The effects of vitamin E deficiency were evaluated in aortic rings i solated from rats maintained on a diet deficient in vitamin E. 2 Endot helium-dependent vasodilator responses to acetylcholine (ACh) and calc ium ionophore, A23187, were reduced in preparations from treated anima ls, compared to the age-matched controls. The maximal vasodilatation t o ACh was 66.4+/-9 (n=4) and 38.8+/-7 (n=4) % in control and 10 month- treated preparations, respectively. 3 The endothelium-independent vaso dilator responses to sodium nitroprusside as well as the concentration -dependent contractile responses to noradrenaline, did not differ betw een treated and control preparations. 4 Electron microscopic examinati on of vascular segments and revealed that, following vitamin E deficie ncy, normal tissue organisation was disrupted, the endothelial monolay er either not being in contact with the underlying tissue or being abs ent in most of the areas analysed. 5 It is concluded that during vitam in E deficiency both morphological disruption and functional impairmen t of endothelium occur without observable modification of muscle cell function and morphology.