Comparative morphologic and histochemical studies on the collagen of vertebrate arteries.

Arteries of representative species from the main vertebrate classes were studied by a method that quantitates collagen-proteoglycans interaction, by the histochemical Picrosirius polarization method and by electron microscopy. The collagen of the adventitia presents features which are characteristic of collagen type I. The collagen in the tunica media revealed histochemical and ultrastructural aspects which are typical of collagen type III. As these results were consistently observed in all species studied, they suggest the presence of a general structural pattern of collagen distribution in vertebrate arteries.