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Evidences for prevention of nitroglycerin tolerance by carvedilol

Ebtehal El-Demerdash1

  • 1Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Abasia, Cairo, Egypt. ebtehal_dm@yahoo.com

Pharmacological Research
|March 1, 2006
PubMed

Insights

Carvedilol, a beta-blocker, prevents nitroglycerin (NTG) tolerance by reducing vascular superoxide production and restoring aortic antioxidants. This study reveals carvedilol

Area of Science:

  • Pharmacology
  • Cardiovascular Research
  • Oxidative Stress Biology

Background:

  • Nitroglycerin (NTG) tolerance is a clinical challenge, often linked to increased vascular superoxide anion (O2-) production.
  • Beta-blockers like carvedilol may offer a protective mechanism against nitrate tolerance.

Purpose of the Study:

  • To investigate the mechanisms by which carvedilol prevents NTG tolerance.
  • To assess carvedilol's effect on vascular O2- production and aortic antioxidant levels.

Main Methods:

  • Rabbits were treated with NTG and/or carvedilol for 3 days.
  • Vascular relaxation, O2- production, glutathione (GSH) levels, and superoxide dismutase (SOD) activity were measured.

Main Results:

  • NTG treatment decreased maximal relaxation and increased vascular O2- production.
  • NTG reduced aortic GSH levels and SOD activity.
  • Carvedilol prevented NTG-induced tolerance, normalized O2- production, and restored GSH and SOD levels.

Conclusions:

  • Carvedilol effectively prevents nitroglycerin tolerance.
  • The protective effect is mediated by reducing vascular O2- production and enhancing antioxidant defense.

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