RESUMO
<p><b>OBJECTIVE</b>To investigate ligand-gated cation channels P2X3 receptors changes in rat pulp during experimental tooth movement (ETM), and preliminarily find their possible effect during ETM.</p><p><b>METHODS</b>54 male SD rats (200-250 g) were selected and randomly divided into blank group (5 rats), control group (14 rats) and experimental group (35 rats). The left maxillary first molar was selected as observation object, the pulp tissue biopsies was taken at different time points to carry out immunohistochemical study.</p><p><b>RESULTS</b>Predominant up regulation of P2X3 receptors immunoactivity was found in pulp from 1/6 d to 7 d after experimental tooth movement. It started to significantly increase at 1/6 d, peaked at 3 d, and then decreased continuously until 7 d as compared with the beginning.</p><p><b>CONCLUSION</b>P2X3 receptors have a rhythm change in rat pulp as a result of ETM, speculated that P2X3 receptors is closely related to the tooth movement injury, but the mechanism of action need further researches.</p>