Abstract
The nasal mucosa and the autonomic nervous regulation of protective reflexes plays an important role for the protection of the lower airways. Increasing experimental evidence from both animal models and humans suggests that the organization of the autonomic nervous pathways is more complicated than previously assumed. Thus a number of biologically active peptides are known to be present in the autonomic pathways and coexist with the classical transmitters. The neuropeptides have experimentally been shown to play an important role in the pathophysiological events in both specific and nonspecific hyperreactivity.