title: Longitudinal study of the hindquarter vasculature during development in spontaneously hypertensive and Dahl salt-sensitive rats.
abstract: The purpose of this study was to examine vascular structural alterations longitudinally in spontaneous and Dahl genetic hypertension. Hypertensive and control animals were studied at 5,9-11, and 17-19 weeks of age to permit analysis of prehypertensive, early and established hypertensive stages. Minimal and maximal resistance of the hindquarter vasculature was used as a functional assessment of structural alterations. At 5 weeks of age, the minimal vascular resistance of the spontaneously hypertensive rats (SHR) was elevated over Wistar-Kyoto (WKY) (p less than 0.02) but there was no difference between Dahl salt-sensitive (S) and resistant (R) rats. In both sets of animals, the minimal vascular resistance of the hypertensive group was significantly elevated over controls with age: p less than 0.001 in SHR; p less than 0.001 in Dahl S. The maximal vasoconstrictor response was significantly greater with age in SHR than in WKY, (p less than 0.001), but was not different in Dahl S compared to R. Thus, structural alterations, determined by assessing minimal vascular resistance, are present in both spontaneous and Dahl salt-sensitive hypertension, but the origin of the two differ. An increase in smooth muscle mass, assessed by maximal constriction, contributes importantly to the structural alterations in spontaneous hypertension; in Dahl S, other factors appear to contribute to structural alterations. Further, structural alterations precede frank hypertension in SHR but not in Dahl S hypertension.
mesh_terms: D000375:Aging; D000818:Animals; D001794:Blood Pressure; D001808:Blood Vessels / Q000187:drug effects / Q000473:pathology*; D001835:Body Weight; D004487:Edema / Q000503:physiopathology; D005260:Female; D006973:Hypertension / Q000473:pathology* / Q000503:physiopathology; D008137:Longitudinal Studies; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance; D014661:Vasoconstriction; D014664:Vasodilation
chemical_list: D009638:Norepinephrine