Multi-walled carbon nanotubes induce airway hyperresponsiveness in human bronchi by stimulating sensory C-fibers and increasing the release of neuronal acetylcholine.

MWCNTs administered at low concentrations elicit AHR in human airways by activating sensory C-fibers and, in turn, increasing the release of neuronal ACh. Our results suggest that work is required to understand the impact of MWCNTs in patients at risk of AHR, such as those suffering from chronic obstructive respiratory disorders.