Electron microscopic study on permeability of the aorta and basilar artery of the rabbit—With special reference to the changes of permeability by hypercholesteremia

Abstract

Morphological characteristies of the rabbit aorta and basilar artery, and their relationship to the permeability pattern were studied at the ultrastructural level, by using H. R. peroxidase and ferritin as the tracers. In addition, the influence of hypercholesteremia on permeability of these arteries was studied. 1. 1. Reaction product of peroxidase and ferritin particles were observed in the caveolae and vesicles of the endothelial cells of the aorta and of the basilar artery. They were also observed in the subendothelial space of the aorta, but not in the basilar artery. The endothelium of the basilar artery was closely applied to the internal elastic lamina and endothelial cells showed a small number of caveolae and vesicles and the presence of tight junction in all of the intercellular space. 2. 2. Unlike the aorta, the intima of the basilar artery showed the barrier function equivalent to the blood-brain barrier of the capillaries in the brain. 3. 3. In the rabbits fed cholesterol for 1 wk, the intima of the aorta showed a slightly enhanced junctional transport. In the rabbits fed colesterol for 16 wk, endothelium overlying the foci of foam cell accumulation in the intima of the aorta showed an enhanced junctional and vescular transport. 4. 4. The intima of the basilar artery showed neither the foci of foam cell accumulation nor altered permeability even in the rabbits fed cholesterol for 16 wk.