Further studies on the development of two-kidney, two clip Goldblatt hypertension in 6-hydroxydopamine-treated rats.

The development of two-kidney, two clip Goldblatt hypertension (2K2C) in the rat seems to be unaffected by chemical sympathectomy with 6-hydroxydopamine (6-HODA) and adrenal demedullation. Since this treatment only partially depletes vascular norepinephrine (NE) content, we evaluated the degree of sympathectomy achieved with the 6-HODA treatment and the structural vascular changes in treated and untreated animals. Litters of male Wistar rats were divided in two groups: 6-HODA-treated (6-HODA) animals (group 1) were injected with 6-HODA since the day of birth until the end of the experiment; control group (CG) animals (group 2) received the vehicle solution. When rats reached about 250 g, a silver clip (0.25 mm width) was placed on both renal arteries in half of them in each group; a sham operation was performed on the rest of the animals. Adrenal demedullation and denervation was performed in all 6-HODA animals. Blood pressure was followed weekly by the tail cuff method for 7 weeks. At the 8th week, Silastic cannulas were placed in the carotid artery and jugular vein in all the animals. Pressor responses to tyramine (0.05 and 0.1 mg), angiotensin (10, 40 and 160 ng), and norepinephrine (NE) (25, 100 and 400 ng) and the hypotensive effect of prazosin (1 mg/kg) were determined in the conscious rats. The pressor effect of carotid occlusion was registered 24 hours later. Animals were sacrificed, and the heart and artery weight as well as the nucleic acids and alkali soluble proteins content in the vascular wall were determined.(ABSTRACT TRUNCATED AT 250 WORDS)