Aortic endothelial junctions in developing hypertension.

The morphology of the intercellular pathway of aortic endothelium was investigated in spontaneously hypertensive rats (SHR) at three different stages in the hypertensive process. Aortic endothelial cells of the SHR, in contrast to those of the normotensive Wistar-Kyoto rats exhibited an increased length and complexity of tight junctions, at all ages studied. That this finding was seen in young SHR, before the elevation of arterial pressure, suggests that other factors (genetic, humoral, neurogenic) may be influencing the morphology of aortic endothelium in the SHR. The area of lateral endothelial membrane occupied by gap junctions also was increased in the SHR, especially at 10 weeks of age, and corresponded to the greatest increase in tight junction strand length and the most rapid and dramatic rise in arterial pressure. The results indicate that aortic endothelium of the SHR can anticipate or respond, and partially adapt, to the abnormal influence of elevated arterial pressure.