Middle cerebral artery occlusion in the hypertensive and normotensive rat: a study of histopathology and behaviour.

Brain infarct size and behaviour were studied in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) 3 weeks after occlusion of the right middle cerebral artery in order to compare the effects of vascular occlusions on the normotensive and hypertensive cerebral vasculature. The brain tissue reduction, assessed by measuring the cross-sectional area of remaining tissue and weight of the cerebral hemispheres, was greater in SHR than in WKY (P less than 0.01). Deficits in sensorimotor integration were highly correlated to the degree of brain damage (r = 0.91). Amphetamine induced no rotation asymmetry in normal rats, whereas lesioned rats rotated more ipsilaterally to the lesion (P less than 0.05). Rotation asymmetry did not correlate with total infarct size. The more severe outcome after middle cerebral artery occlusion in SHR as opposed to WKY, can probably be explained by reduced collateral capacity secondary to the altered vascular design in hypertension.