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Catecholamine, dopamine-beta-hydroxylase and atrial natriuretic factor content in separate heart chambers of
1Clinical Research Institute of Montreal, Université de Montréal, Quebec, Canada.
Insights
Cardiomyopathy alters atrial natriuretic factor (ANF) and catecholamine (CA) levels differently in hamster atria and ventricles. Dopamine-beta-hydroxylase (D beta H) activity changes do not correlate simply with norepinephrine depletion or ANF levels.
Area of Science:
- Cardiovascular Physiology
- Neuroendocrinology
- Biochemistry
Background:
- Previous studies suggest a link between atrial natriuretic factor (ANF) and dopamine-beta-hydroxylase (D beta H).
- Cardiomyopathic hamsters exhibit decreased atrial and increased ventricular ANF concentrations.
- Catecholamine (CA) and D beta H levels in cardiac tissues are of interest in cardiomyopathy.
Purpose of the Study:
- To investigate atrial and ventricular catecholamine (CA) and dopamine-beta-hydroxylase (D beta H) content in cardiomyopathic hamsters.
- To correlate these findings with altered atrial and ventricular ANF concentrations.
- To elucidate the mechanisms of norepinephrine (NE) depletion in cardiac compartments.
Main Methods:
- Assessed atrial and ventricular catecholamine (CA) and dopamine-beta-hydroxylase (D beta H) content in hamsters with progressive cardiomyopathy.
- Measured atrial natriuretic factor (ANF) concentrations in parallel.
- Correlated tissue NE levels with D beta H activity and ANF concentrations.
Main Results:
- Progressive cardiomyopathy led to reduced atrial NE content paralleling declining D beta H activity.
- In ventricles, decreasing NE content was associated with increased D beta H activity.
- No simple relationship was found between NE depletion and D beta H activity, or between D beta H activity and ANF concentrations.
Conclusions:
- Norepinephrine (NE) depletion mechanisms differ between the atria and ventricles in this model.
- The data do not support a direct relationship between NE depletion, D beta H activity, and ANF levels.
- Further research is needed to understand the complex interplay of these factors in cardiomyopathy.
Abstract:
Since previous investigations have suggested a relationship between atrial natriuretic factor (ANF) and dopamine-beta-hydroxylation, cardiomyopathic hamsters were studied for atrial and ventricular catecholamine (CA) and dopamine-beta-hydroxylase (D beta H) content as correlates to a parallel finding of markedly decreased atrial but increased ventricular ANF concentrations in these animals. It was noted that, with progressive cardiomyopathy, the reduced tissue norepinephrine (NE) content paralleled the declining D beta H activity in the atria. In the ventricles, however, the progressively-decreasing NE content was associated with an increase of D beta H. These data indicate that the NE depletion is mediated by different mechanisms in the ventricles and atria. They do not support a simple relationship between NE depletion and tissue D beta H activity or between the latter and tissue ANF concentrations.