The Adrenergic Innervation in the Esophagus and Respiratory Tract of the Rabbit

Abstract

The mode of innervation of the adrenergic nerve fibers in the esophagus and respiratory tract of the rabbit was observed fluoro-histochemically. The noradrenaline fluorescent fibers in the esophagus were found to distribute in the subniucosa, lamina muscularis mucosa, muscle layers, and around the myenteric ganglion cell. The dense distribution of the fibers around the myenteric plexus, arteries, and arterioles showed the net structures with varicose terminals, indicating active regulation of the structures. The fluorescent fibers in the trachea were found to distribute in the subniucosa and muscular layers by penetrating the fibro-elastic layer and membraneous portion of the subniucosa. The distribution of the fluorescent fibers in the lung was relatively abundant around the pulmonary arteries, but the smooth muscle of the bronchiole exhibited a few fluorescent fibers, which were completely absent from the alveoles.