Studies of isolated resistance vessels from offspring of essential hypertensive patients.

In order to investigate whether functional and morphological changes are present in the resistance vasculature before hypertension is established, isolated subcutaneous resistance vessels were studied from 21 young normotensive subjects with a family history of hypertension and 22 controls matched for age, sex, and weight. The vessels from the offspring of hypertensive patients displayed no morphological changes or differences in reactivity or sensitivity to the vasoconstrictor agonists norepinephrine, angiotensin II, serotonin, and vasopressin. In the presence of cocaine, however, vessels from offspring showed a significantly greater shift in sensitivity to norepinephrine, a phenomenon also observed in previous studies of vessels from hypertensive patients. The results suggest that in essential hypertension, while morphological and functional abnormalities of the resistance vasculature may develop as the blood pressure rises, a defect in neuroeffector activity is present before hypertension is established and may be a manifestation of abnormal sympathetic nervous system activity underlying the disease.