Monoaminergic pathways to the coronary arteries and to the myocardium.

The monoaminergic innervation of the coronary vessels and of the myocardium in dogs was examined by means of degenerative techniques: (i) local perivascular neurotomy was performed at the origin of the left coronary artery; (ii) the stellate ganglion was removed bilaterally. Evaluation of the neural degeneration pattern led the suggestion that three types of neurons at least exist within the heart: (i) neurons innervating the coronary vessels both in the ventricles and in the atria; (ii) neurons innervating the ventricular myocardium, and (iii) neurons innervating the atrial myocardium. The post-ganglionic fibres of the stellate ganglion innervate the vessels of the whole heart. Their contribution to the innervation of the ventricular myocardium represents about 30%.