Nitric oxide release from normal and dysfunctional endothelium

V. Brovkovych, L. W. Dobrucki, S. Brovkovych, I. Dobrucki, C. A. Do Nascimento, A. Burewicz, T. Malinski

Research output: Contribution to journalArticlepeer-review


The endothelium plays a critical role in maintaining vascular tone by releasing vasoconstrictor and vasodilator substances. Endothelium - derived nitric oxide (NO) is a vasodilator rapidly inactivated by superoxide (O-2) found in significant quantities. The porphyrinic sensor (0.5-8 μm diameter) and chemiluminescence methods were used to measure NO and O-2 respectively. Effects of hypertension, low density lipoprotein (LDL), and heart preservation on the release of NO and O-2 were delineated. In the single endothelial cell (rat aorta) NO concentration was the highest in the cell membrane decreasing exponentially with distance from cell, and becoming undetectable beyond 50 μm and 25 μm for normotensive (WKY) and hypertensive (SHR) rats respectively. The endothelium of SHR released 40% less NO (300 ± 25 nmol L-1) than that of normotensive rats (500 ± 20 nmol L-1), due to the higher production of O-2 in SHR rats. An exponentially decreasing NO production (from 1.20 ± 0.15 to 0.10 ± 0.05 μmol L-1) and concomitant increase of O-2 generation (from 10±0.3 to 300 ± 25 nmol L-1) were observed in left ventricle of stored (eight hours) rabbit heart. Native and oxidized low density lipoproteins (nLDL and oxLDL) inhibited NO generation and increased O-2 production. The local depletion of the L-arginine substrate may disarrange the nitric oxide synthase, leading to production of O-2 from oxygen.

Original languageEnglish (US)
Pages (from-to)575-586
Number of pages12
JournalJournal of Physiology and Pharmacology
Issue number4
StatePublished - Dec 1999
Externally publishedYes


  • Endothelium
  • Free radicals
  • Nitric oxide
  • Superoxide
  • Vascular system

ASJC Scopus subject areas

  • Pharmacology
  • Physiology

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