ABSTRACT
This chapter discusses the role of membrane-bound peptidases in modulating neurogenic inflammation. It presents the evidence that decreased peptidase activity in airways results in exaggerated neurogenic inflammatory responses and that increased peptidase activity decreases neurogenic inflammatory responses. In vitro, tachykinins are degraded by various enzymes, including serine proteases, mast cell chymase, calpains , neutral endopeptidase, and angiotensin-converting enzyme. However, only two enzymes are known to play roles in the normal modulation of neurogenic inflammation in vivo: neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE). From the anatomical localization of NEP and the sites of neuropeptide release, it has been suggested that NEP modulates neurogenic inflammatory responses both at sites of neuropeptide release and at sites of neuropeptide actions. Up-and-down regulation of these peptidases has profound effects on neurogenic inflammatory responses. Selective inhibitors of NEP and ACE have been developed, and they have been useful in assessing the role of peptidases in modulating neurogenic inflammation.
