In vitro pharmacological characterization of a novel TRPA1 antagonist and proof of mechanism in a human dental pulp model.

AZ465 is a novel selective transient receptor potential cation channel, member A1 (TRPA1) antagonist identified during a focused drug discovery effort. In vitro, AZ465 fully inhibits activation by zinc, O-chlorobenzylidene malononitrile (CS), or cinnamaldehyde of the human TRPA1 channel heterologously expressed in human embryonic kidney cells. Our data using patch-clamp recordings and mouse/human TRPA1 chimeras suggest that AZ465 binds reversibly in the pore region of the human TRPA1 channel. Finally, in an ex vivo model measuring TRPA1 agonist-stimulated release of neuropeptides from human dental pulp biopsies, AZD465 was able to block 50%-60% of CS-induced calcitonin gene-related peptide release, confirming that AZ465 inhibits the native human TRPA1 channel in neuronal tissue.