The purinoreceptor, P2X₃ is a ligand-gated cation channel activated by extracellular ATP. It has been reported that ATP can be released during inflammation and tissue damage, which in turn may activate P2X₃ receptors to initiate nociceptive signals. However, little is known about the contribution of P2X₃ to the dental pain during pulpal inflammation. Therefore, the purpose of this study was to investigate the expression of P2X₃ and its colocalization with TRPV1 to understand the mechanism of pain transmission through P2X₃ in the human dental pulp with double labeling immunofluorescence method.

In the human dental pulp, intense P2X₃ immunoreactivity was observed throughout the coronal and radicular pulp. Of all P2X₃-positive fibers examined, 79.4% coexpressed TRPV1.

This result suggests that P2X₃ along with TRPV1 may be involved in the transmission of pain and potentiation of noxious stimuli during pulpal inflammation.