Maintenance of endothelin-induced renal arteriolar constriction in rats is cyclooxygenase dependent

K. A. Munger, K. Takahashi, M. Awazu, M. Frazer, S. A. Falk, J. D. Conger, K. F. Badr

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Abstract

Influence of arachidonate cyclooxygenase (COX) products on endothelin (ET)-evoked renal vasoconstriction was assessed. In microperfused rat afferent (AA) and efferent arterioles (EA), indomethacin had no effects on the maximal contraction of both AA and EA by ET, but reduced the duration of ET-induced constriction in both arterioles. ET infusion to rats in vivo resulted in a selective increase in efferent but not afferent arteriolar resistance, leading to a dramatic increase in transcapillary hydraulic pressure difference. Glomerular filtration rate (GFR), which fell progressively during infusion of ET alone, was markedly preserved by COX inhibition, but not during selective thromboxane A2 antagonism. In isolated glomeruli, release of prostaglandin (PG) F(2α) in response to 10-6 mol/l ET exceeded that of PGE2 by a ratio of 3:2. Collectively, these data provide strong evidence that locally released COX products, possibly PGF(2α), play a key role in sustaining ET-induced renal arteriolar constriction. COX inhibition leads to acute vasorelaxation of AA despite continued ET administration, without affecting EA constriction in vivo, thereby resulting in a dramatic reversal of the effects of ET on GFR.

Original languageEnglish
Pages (from-to)F637-F644
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Volume264
Issue number4 33-4
Publication statusPublished - 1993 Jan 1

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Keywords

  • arteriole
  • glomeruli
  • hemodynamics
  • prostaglandins
  • thromboxane

ASJC Scopus subject areas

  • Physiology

Cite this

Munger, K. A., Takahashi, K., Awazu, M., Frazer, M., Falk, S. A., Conger, J. D., & Badr, K. F. (1993). Maintenance of endothelin-induced renal arteriolar constriction in rats is cyclooxygenase dependent. American Journal of Physiology - Renal Fluid and Electrolyte Physiology, 264(4 33-4), F637-F644.