The influence of aging and hypertension on cerebral autoregulation

Cerebral autoregulation was tested here in 3- and 18-month-old spontaneously hypertensive rats (SHR) and Wistar Kyoto controls (WKY). Cerebral blood flow (CBF) was measured in each rat using radioactive micropheres under unanesthetized control conditions and after hypotension induced by ganglionic blockade. Under control conditions there was no significant difference in CBF between SHR and WKY. During drug induced hypotension CBF decreased significantly in all except 3 month WKY. CBF was decreased significantly more in 18 month SHR after ganglionic blockade compared to other test groups. These results indicate an influence of both age and hypertension in altering the ability of the cerebrovasculature to autoregulate.