Effects of the Angiotensin I Converting Enzyme Inhibitor Perindopril on Cerebral Blood Flow in Awake Hypertensive Rats

As chronic hypertension shifts the lower limit of cerebral blood flow (CBF) autoregulation to higher pressure levels, we studied the effects of t h e angiotensin converting enzyme (ACE) inhibitor, perindopril on mean arterial pressure (mean BP), basal CBF, and CBF autoregulation in awake renovascular hypertensive (2 kidneys, 1 clip model) and spontaneously hypertensive rats (SHR). Blood pressure was measured via a chronically implanted arterial cannula and CBF b y hydrogen clearance. Chronic renovascular hypertension, like spontaneous hypertension, caused a marked shift in t h e lower limit of CBF autoregulation but did not alter basal CBF. In SHR, acute administration of perindopril did not diminish CBF in spite of the fact that BP fell to a level below the lower limit of CBF autoregulation (determined b y hypotensive hemorrhage). Chronic treatment of renovascular hypertensive rats with perindopril normalized BP and restored CBF autoregulation. Am J Hypertens 1991;4:246S-252S