Distribution of Norepinephrine in the Failing Bovine Heart
Correlation of Chemical Analysis and Fluorescence Microscopy
Studies were carried out during experimental heart failure induced in calves to compare the depletion of cardiac norepinephrine in the failing heart to the histochemical appearance of the adrenergic innervation in this tissue. A correlation has been established between the reduction of norepinephrine concentration and the changes in the distribution of the adrenergic neurotransmitter in the tissues. Absence of fluorescence in terminal varicose fibers in close association with cardiac muscle cells was characteristic of the failing heart. Little or no change occurred in preterminal fibers or in terminal fibers in connective tissue septa or around blood vessels. In two steers, recovery from heart failure was shown to be associated with a virtual restoration of the norepinephrine concentration and of thehistochemical appearance of the adrenergic nerve distribution in 28 days or less. These findings suggest that a reversible abnormality, possibly of neurotransmitter storage or synthesis, or both, is induced in the terminal portion of the cardiac adrenergic innervation as the result of the development of the failure state.
- Accepted November 1, 1968.
- © 1969 American Heart Association, Inc.