ABSTRACT
Many neuropeptides have been localized to the respiratory tract of animals and humans (1-4) (Table 1). These peptides may have potent effects on airway function and may play a role in the pathophysiological processes of airway disease. Some of these peptides, such as vasoactive intestinal polypeptide (VIP), may play an antiinflammatory role, whereas others, such as substance P (SP), may amplify the inflammatory process. Although the functional role of these peptides has been studied extensively in animal models, there is still relatively little information about the role of neuropeptides in human airways, particularly in disease. There is increasing evidence for plasticity in the nervous system and it is likely that many neuropeptide and neuropeptide receptor genes are abnormally expressed in disease, in response to inflammatory cytokine and other signals genemted in the inflammatory response. The altered expression of neuropeptides may then lead to enhanced neural control of airways. Although there is increasing information about the effects on the airways of different neuropeptides, the role of neuropeptides in airway inflammatory disease is likely to become apparent only when the effects of specific neuropeptide antagonists or release inhibitors are studied in affected patients. Recently several potent tachykinin antagonists
Table 1 Neuropeptides in the Respiratory Tract
Peptide
Vasoactive intestinal peptide Peptide histidine isoleucine/methionine Peptide histidine valine 42 Helodennin Helospectins I and II PACAP-27 Galanin Adrenomedullin
Substance P Neurokinin A Neuropeptide K Calcitonin gene-related peptide Gastrin-releasing peptide
Neuropeptide Y Somatostatin
Enkephalin Nociceptin?
