Mechanotransducers in rat pulpal afferents

The hydrodynamic theory suggests that pain associated with stimulation of a sensitive tooth ultimately involves mechanotransduction as a consequence of fluid movement within exposed dentinal tubules. To determine whether putative meehanotransducers could underlie mechanotransduction in pulpal afferents, we used a single-cell PCR approach to screen retrogradely labeled pulpal afferents. The presence of mRNA encoding BNC-1, ASIC3, TRPV4, TRPA1, the α, β, and γ subunits of ENaC, and the two pore K⁺ channels (TREK1, TREK2) and TRAAK were screened in pulpal neurons from rats with and without pulpal inflammation. ASIC3, TRPA1, TRJEK1, and TREK2 were present in ∼67%, 64%, 14%, and 10% of pulpal neurons, respectively. There was no detectable influence of inflammation on the proportion of neurons expressing these meehanotransducers. Given that the majority of pulpal afferents express ASICS and TRPA1, our results raise the possibility that these channels may be novel targets for the treatment of dentin sensitivity.