Effect of acute arterial hypertension in stroke-prone and stroke-resistant SHR.

Acute transient hypertension by norepinephrine was loaded to stroke-resistant (SHRSR), stroke-prone (SHRSP), and normotensive Wistar Kyoto (WK) rats. (SHRSP were most sensitive to norepinephrine in young pre-hypertensive group.) Its effects on cerebral small vessels were studied using Evans Blue to detect the increase of vascular permeability. Severe macroscopic dye-leakages were observed in the areas of "recurrent branching" and "boundary zone", especially among young SHRSP, while SHRSR seemed to be least prone to dye-leakage both in young and adult groups. Among the adults, there was little difference between SHRSP and WK, probably because of the adaptive structural changes of arterial walls in SHRSP caused by long-standing hypertension.