Thromboxane is required for full expression of angiotensin hypertension in rats

Henry L. Keen, Michael W Brands, Manis J. Smith, Eugene W. Shek, John E. Hall

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Recent studies suggest that thromboxane (TX) mediates a significant component of angiotensin II (ANG II)-induced hypertension. However, there is little information to support the hypothesis that this relationship is important during chronic, physiological increases in ANG II, particularly while controlling for variation in endogenous ANG II levels induced by TX inhibition. This study tested that hypothesis in 27 chronically instrumented rats. After baseline measurements, suppression of endogenous TX was induced and maintained throughout the study in 13 rats by IV infusion of the TX synthesis inhibitor (TSI) U63557A; the other 14 rats received vehicle. Baseline mean arterial pressure (MAP) was not different between groups and was unchanged by TSI or vehicle. Continuous inhibition of ANG II production was then initiated in both groups of rats by IV infusion of the angiotensin- converting enzyme inhibitor (ACEI) benazepril. ACEI reduced blood pressure similarly in vehicle and TSI rats, from 105±2 to 91±2 mm Hg and 103±1 to 89±1 mm Hg, respectively. ANG II was then infused at 5 ng · kg-1 · min- 1 IV for 7 days in six rats from each group to restore ANG II activity to baseline levels. This dose increased MAP to 103±2 and 101±1 mm Hg in vehicle and TSI rats, respectively, values not different from pre-ACEI levels. Seven TSI rats and eight vehicle rats received a higher dose of ANG II (20 ng · kg-1 · min-1 IV). After 7 days, MAP was higher in vehicle than in TSI rats (143±5 versus 120±4 mm Hg). These results suggest that endogenous TX is an important determinant of MAP in ANG II hypertension but may have a diminished role in blood pressure regulation when ANG II is at normal and subnormal levels.

Original languageEnglish (US)
Pages (from-to)310-314
Number of pages5
JournalHypertension
Volume29
Issue number1 II
StatePublished - Jan 1 1997
Externally publishedYes

Fingerprint

Thromboxanes
Angiotensins
Angiotensin II
Hypertension
Arterial Pressure
Angiotensin-Converting Enzyme Inhibitors
Blood Pressure

Keywords

  • angiotensin II
  • blood pressure
  • hypertension
  • thromboxane

ASJC Scopus subject areas

  • Internal Medicine

Cite this

Keen, H. L., Brands, M. W., Smith, M. J., Shek, E. W., & Hall, J. E. (1997). Thromboxane is required for full expression of angiotensin hypertension in rats. Hypertension, 29(1 II), 310-314.

Thromboxane is required for full expression of angiotensin hypertension in rats. / Keen, Henry L.; Brands, Michael W; Smith, Manis J.; Shek, Eugene W.; Hall, John E.

In: Hypertension, Vol. 29, No. 1 II, 01.01.1997, p. 310-314.

Research output: Contribution to journalArticle

Keen, HL, Brands, MW, Smith, MJ, Shek, EW & Hall, JE 1997, 'Thromboxane is required for full expression of angiotensin hypertension in rats', Hypertension, vol. 29, no. 1 II, pp. 310-314.
Keen HL, Brands MW, Smith MJ, Shek EW, Hall JE. Thromboxane is required for full expression of angiotensin hypertension in rats. Hypertension. 1997 Jan 1;29(1 II):310-314.
Keen, Henry L. ; Brands, Michael W ; Smith, Manis J. ; Shek, Eugene W. ; Hall, John E. / Thromboxane is required for full expression of angiotensin hypertension in rats. In: Hypertension. 1997 ; Vol. 29, No. 1 II. pp. 310-314.
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