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Assessment of Vascular Tone Responsiveness using Isolated Mesenteric Arteries with a Focus on Modulation by Perivascular Adipose Tissues
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Published on: June 3, 2019

Altered arachidonic acid metabolism impairs functional vasodilation in metabolic syndrome

Lusha Xiang1, Jay S Naik, Benjamin L Hodnett

  • 1Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State St., Jackson, MS 39216-4505, USA.

American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
|September 17, 2005
PubMed

Insights

Obese Zucker rats exhibit impaired vasodilation due to increased thromboxane receptor (TP) vasoconstriction and reduced prostacyclin (PGI2) vasodilation, impacting metabolic syndrome. Blocking TP receptors improved blood vessel function in these rats.

Area of Science:

  • Vascular biology
  • Metabolic syndrome research
  • Cardiovascular physiology

Background:

  • Obesity and metabolic syndrome are linked to impaired vascular function.
  • Obese Zucker rats (OZRs) serve as a model for metabolic syndrome, exhibiting endothelial dysfunction.
  • Understanding the mechanisms of impaired vasodilation is crucial for therapeutic development.

Purpose of the Study:

  • To investigate the roles of thromboxane receptor (TP)-mediated vasoconstriction and prostacyclin (PGI2)-induced vasodilation in the impaired functional vasodilation observed in obese Zucker rats (OZRs).

Main Methods:

  • Microcirculatory observations of spinotrapezius arcade arterioles from lean (LZR) and obese Zucker rats (OZR).
  • Measurement of arteriolar diameter following muscle stimulation, TP receptor antagonism (SQ-29548), and administration of prostacyclin analog (iloprost), arachidonic acid, sodium nitroprusside, and adenosine.
  • Assessment of vasodilatory responses in the absence and presence of a TP antagonist.

Main Results:

  • Functional hyperemia and arachidonic acid-mediated vasodilation were significantly reduced in OZRs compared to LZRs.
  • TP receptor antagonism with SQ-29548 enhanced vasodilation in OZRs but not LZRs.
  • Vasodilatory responses to iloprost and sodium nitroprusside were significantly diminished in OZRs.

Conclusions:

  • The impaired functional vasodilation in obese Zucker rats is attributed to heightened TP-mediated vasoconstriction.
  • Reduced prostacyclin (PGI2)-induced vasodilation also contributes to the vascular dysfunction in this metabolic syndrome model.
  • Targeting TP receptor activity may offer a therapeutic strategy for vascular impairments in metabolic syndrome.

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