Renal medullary captopril delivery lowers blood pressure in spontaneously hypertensive rats

Shanhong Lu, David L. Mattson, Allen W. Cowley

Research output: Contribution to journalArticle

Abstract

We examined the contribution of renal medullary function to the maintenance of hypertension in spontaneously hypertensive rats by infusing captopril chronically into the renal medullary interstitial space of uninephrectomized rats. Changes in cortical and medullary blood flow were determined using a newly developed optical fiber implantation technique for laser-Doppler flowmetry. Renal medullary interstitial infusion of captopril (5 mg/kg per day) selectively increased medullary blood flow by 40% without altering renal cortical blood flow throughout the 5 days of captopril delivery. In association with the selective increase of medullary perfusion, a significant natriuresis was observed on the second day of the drug infusion, and urine osmolality was significantly reduced during the first 3 days of captopril infusion. Mean arterial pressure was significantly decreased by 20 mm Hg during 5 days of captopril infusion, and the chronic renal function curve was shifted to a lower level of arterial pressure compared with the control values when 0.9% sodium chloride saline vehicle was infused. Intravenously infused captopril at 5 mg/kg per day did not alter mean arterial pressure, excluding the possibility that the hypotensive effect of medullary captopril infusion was due to recirculation. In summary, chronic reduction of the elevated renal medullary vascular tone by medullary interstitial infusion of captopril reset the steady-state renal function curve and lowered arterial pressure in spontaneously hypertensive rats.

Original languageEnglish (US)
Pages (from-to)337-345
Number of pages9
JournalHypertension
Volume23
Issue number3
DOIs
StatePublished - Mar 1994
Externally publishedYes

Fingerprint

Captopril
Inbred SHR Rats
Blood Pressure
Kidney
Arterial Pressure
Optical Fibers
Natriuresis
Laser-Doppler Flowmetry
Renal Circulation
Sodium Chloride
Osmolar Concentration
Blood Vessels
Perfusion
Maintenance
Urine
Hypertension
Pharmaceutical Preparations

Keywords

  • captopril
  • hemodynamics
  • kidney
  • kidney medulla
  • rats, inbred SHR

ASJC Scopus subject areas

  • Internal Medicine

Cite this

Renal medullary captopril delivery lowers blood pressure in spontaneously hypertensive rats. / Lu, Shanhong; Mattson, David L.; Cowley, Allen W.

In: Hypertension, Vol. 23, No. 3, 03.1994, p. 337-345.

Research output: Contribution to journalArticle

Lu, Shanhong ; Mattson, David L. ; Cowley, Allen W. / Renal medullary captopril delivery lowers blood pressure in spontaneously hypertensive rats. In: Hypertension. 1994 ; Vol. 23, No. 3. pp. 337-345.
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