Protective effect of treatment with nicardipine on cerebrovascular tree ofspontaneously hypertensive rats

The effect of an eight-week treatment with the Ca2+ channel blocker nicardi pine on different-sized pial arteries acid intracerebral arteries was asses sed in spontaneously hypertensive rats (SHR) by microanatomical techniques. Normotensive Wistar-Kyoto (WKY) rats were used as normotensive reference a nimals. In SHR a significant increase of systolic blood pressure (SBP) in c omparison with WKY rats was noticeable. An increased thickness of tunica me dia and luminal narrowing were also seen in medium- and small-sized pial ar teries, and in intracerebral arteries of SHR in comparison with WKY rats. T he media-to-lumen ratio was also increased in medium (diameter between 150 and 50 mum) and small-sized (diameter < than 50 <mu>m) pial and intracerebr al arteries. Treatment with nicardipine significantly reduced SEP, the thic kness of tunica media, media-to-lumen ratio and increased luminal area of m edium- and small-sized pial arteries and of intracerebral arteries. These f indings demonstrate that treatment of SHR with nicardipine induces a modera te vasodilatation of both pial and intracerebral arteries regulating cerebr ovascular resistance. This property may be useful in avoiding generalized or exaggerated cerebrov ascular dilatation in hypertension which could be accompanied by impaired b rain perfusion.