Role of dopamine in the striatum, renin-angiotensin system and renal sympathetic nerve on the development of two-kidney, one-clip Goldblatt hypertension.

PURPOSE

The possible role of the striatum and renin-angiotensin (R-A) system for the development of two kidney-one clip (2K-1C) Goldblatt hypertension is examined.

MATERIALS AND METHODS

Monoamine contents of the striatum were determined by brain dialysis techniques, and plasma and kidney levels of the R-A system were measured by radioimmunoassay in sham-operated rats (experiment 1), 2K-1C hypertension (experiment 2), left renal denervation only (experiment 3), renal denervation of left clipped-kidney (experiment 4) and left renal artery clipping with renal denervation of right nonclipped kidney (experiment 5) in the acute phase.

RESULTS

Plasma angiotensin I (ANG I) and plasma angiotensin II (ANG II) were initially increased between the first day and the first week, were suppressed at the second week, then increased again at the third week. Renal denervation of clipped or nonclipped kidneys did not influence the plasma R-A system in 2K-1C rats. The levels of striatum dopamine (DA), dihidroxyphenylacetic acid (Dopac) and homovanillic acid (HVA) in hypertensive 2K-1C rats were higher than those in normotensive sham-operated rats. There were significant positive relationships between these monoamines and systolic blood pressure. Renal levels of ANG I, II and angiotensin I converting enzyme activity (ACE) in the clipped-kidney were significantly higher than in sham-operated and nonclipped kidneys of 2K-1C rats.

CONCLUSION

The enhanced R-A system in clipped-kidney and high levels of monoamines described above in the striatum appear to participate in the development of 2K-1C hypertensive rats.