NGF and chronic obstructive pulmonary disease: TRPA1 can also be activated chronically in chronic cough, asthma, chronic obstructive pulmonary disease (COPD), and rhinitis, wherein endogenous TRPA1 ligands (e.g., 4HNE, H2O2) and pro-inflammatory mediators (e.g., bradykinin and nerve growth factors) are elevated (Dolovich et al. 1970; Winterbourn and Kettle 2000).