Related Experiment Videos
Nitric oxide synthase activities in human myocardium
A J de Belder1, M W Radomski, H J Why
1Department of Cardiology, King's College Hospital, London, UK.
Lancet (London, England)
|January 9, 1993
Summary
The human heart can produce both constitutive and inducible nitric oxide (NO) synthases. In dilated cardiomyopathy, inducible NO synthase activity increases while constitutive activity decreases, suggesting a dual role for NO in heart health and disease.
Area of Science:
- Cardiology
- Biochemistry
- Molecular Biology
Background:
- Nitric oxide (NO) is a crucial signaling molecule in cardiovascular function.
- Two main isoforms of NO synthase (NOS) exist: constitutive (cNOS) and inducible (iNOS).
- The roles of cNOS and iNOS in human dilated cardiomyopathy (DCM) remain incompletely understood.
Purpose of the Study:
- To investigate the activities of both cNOS and iNOS in myocardial tissue from patients with DCM.
- To determine the relationship between cNOS and iNOS activities in the failing human heart.
Main Methods:
- Myocardial tissue samples were obtained from the right ventricle of 17 DCM patients.
- Enzyme activity assays were performed to quantify cNOS and iNOS activities.
Main Results:
- Significant iNOS activity was detected in the myocardium of DCM patients.
- A concurrent low activity of cNOS was observed in these patients.
- These findings indicate the myocardium's capacity to express both NOS isoforms.
Conclusions:
- The human myocardium possesses the ability to express both constitutive and inducible nitric oxide synthases.
- Altered balance between cNOS and iNOS may contribute to the pathophysiology of DCM.
- Nitric oxide likely plays both physiological and pathological roles in the human heart, particularly in the context of dilated cardiomyopathy.