[Changes in the morphometric indices of the microvascular bed of the brain in experimental hypertension].

Brain stem microvessels up to 15 microns in diameter of spontaneously hypertensive rats and rats with experimental renal hypertension were investigated in histological sections with the aid of a texture analysis system. Hypertensive animals showed a reduction in the vascular diameter per unit volume of cerebral tissue, in the mean vascular diameter as well as in the area occupied by the vessels, thus attesting to the lessened density of brain vascularization. The proportion of the vessels measuring from 6 to 15 microns in diameter per unit volume of cerebral tissue decreased whereas the proportion of the vessels measuring up to 5 microns in diameter remained unchanged. The characteristics under study demonstrated the same line of changes in both spontaneous and experimental renal hypertension.