Calcitonin gene-related peptide: role in airway homeostasis.

The lung is an important source of sensory neuropeptides that modulate airway function in health and disease. Among these neuropeptides, calcitonin gene-related peptide (CGRP) plays a prominent role. CGRP is constitutively expressed in normal lungs where it localizes to a specialized subset of epithelial cells (neuroendocrine cells) and sensory C fibers distributed to pulmonary airways, blood vessels and lymphoid tissue. CGRP can mediate multiple effects, some of which have potential implications in airway homeostasis. These include vasoregulation, bronchoprotection, anti-inflammatory actions and tissue repair. Targeting these effects of CGRP could be a future avenue for modulation of certain aspects of airway diseases.