Morphometric study on cerebral vessels in spontaneously hypertensive rats

Abstract

The ratio between media thickness and lumen radlus was determined in cerebral arterial vessels of 15- and 200-day-old spontaneously hypertensive (SHR) and normotensive rats (Kyoto Wistar and local Wistar rats). A modification of Furuyama’s morphometrical method was used. There was a statistically significant increase of media/radius ratio among medium size and large vessels in 15-day-old SHR. Furthermore, the media cross section area and lumen radius was increased in the internal carotid arteries of young SHR. These early vascular aberrations could be caused by the slight increase of blood pressure at this age or be due to other genetically determined mechanisms in SHR. In 200-day-old SHR a significantly increased media/radius ratio was seen in arterial vessels with a radius <80 μm when compared to local Wistar rats but only in the smallest arterioles (r < 20 μm) when compared to Kyoto Wistar rats. The present results offer a likely explanation for the increased cerebrovascular resistance during maximum vasodilatation in SHR. © 1980 American Heart Association, Inc.