The autonomic innervation of the human vocal cord: neuropeptides

Three methods have been used to study the sympathetic and parasympathetic innervation of the vocal cord: paraformaldehyde-induced fluorescence, electron microscopy, and the peroxidase-antiperoxidase technique. Each method has been successful in determining adrenergic fibers, autonomic endings, and the neuropeptides VIP and NPY, respectively. The close relationship between these neuropeptides and the autonomic endings (adrenergic and cholinergic), and the presence of the neuropeptides in the chorion of the vocal cord, around glands and vessels, gives new evidence that autonomic innervation plays a role in the functioning of this part of the larynx.