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Nitric oxide release from porcine mitral valves
1Department of Pharmacology and Therapeutics, University of Wales College of Medicine, Heath Park, Cardiff, United Kingdom.
Cardiovascular Research
|September 1, 1993
Summary
Porcine mitral valves release nitric oxide (NO) under basal conditions. This release, primarily from the endocardial endothelium, is stimulated by agonists and is calcium-dependent.
Area of Science:
- Cardiovascular Biology
- Biochemistry
- Physiology
Background:
- Nitric oxide (NO) plays a crucial role in vascular function.
- The role of NO in heart valve physiology is not fully understood.
Purpose of the Study:
- To investigate the release of nitric oxide (NO) from porcine mitral valves.
- To identify agonists that stimulate NO release and factors influencing its synthesis.
Main Methods:
- Porcine mitral valves were perfused with Holman solution.
- NO release was detected using a bioassay cascade system and a chemiluminescent method.
- NO synthase inhibitors and calcium-free conditions were employed to study synthesis pathways.
Main Results:
- Porcine mitral valves release NO under basal conditions.
- Agonists including ADP, substance P, bradykinin, thrombin, and A23187 stimulated NO release, with ADP being most potent.
- NO release was inhibited by NO synthase inhibitors (specifically L-NMMA for agonist-stimulated release) and calcium depletion.
Conclusions:
- The endocardial endothelium of mitral valves is a source of NO.
- NO synthesis is calcium-dependent and influenced by various agonists.
- Distinct mechanisms may govern basal and agonist-stimulated NO release.