Chronology and mode of reinnervation of the surgically denervated canine heart: functional and chemical correlates.

This study was undertaken to evaluate functionally the time and pattern of inotropic and chronotropic efferent cardiac reinnervation of the deneravated canine heart and to correlate functional data with regional myocardial catecholamine content and supersensitivity to norepinephrine. Our data indicate that efferent autonomic reinnervation takes place first in the atria, followed by a base-to-apex sequence in the ventricles, and that such reinnervation is functionally effective 9-12 mo after denervation. The return of neural function parallels the return of measurable quantities of myocardial norepinephrine and is accompanied by a decrease in supersensitivity to exogenous norepinephrine. The return to apparently complete functional reinnervation, however, cannot be quantitatively related to myocardial levels of catecholamine. Segmental myocardial supersensitivity to norepinephrine is sequentially reversed during progressive adrenergic reinnervation.